Human sexuality

This article is about human sexual anatomy, sexuality and perceptions. For information specifically about sexual activities, see Human sexual activity. For sexual behavior among other animals, see Animal sexual behaviour. For other uses, see Sexuality (disambiguation).

Human sexuality is the capacity to have erotic experiences and responses. A person's sexual orientation may influence their sexual interest and attraction for another person. Sexuality can have biological, emotional/physical or spiritual aspects. The biological aspect of sexuality refers to the reproductive mechanism as well as the basic biological drive that exists in all species, which is hormonally controlled. The emotional or physical aspect of sexuality refers to the bond that exists between individuals, and is expressed through profound feelings or physical manifestations of emotions of love, trust, and caring. There is also a spiritual aspect of sexuality of an individual or as a connection with others. Sexuality impacts and is impacted by cultural, political, legal, and philosophical aspects of life. It can refer to issues of morality, ethics, theology, spirituality, or religion. Some cultures have been described as sexually repressive.

Interest in sexual activity typically increases when an individual reaches puberty. Some researchers assume that sexual behavior is determined by genetics, and others assert that it is molded by the environment. This is the nature versus nurture debate, in which one can define nature as those behavioral traits that are due to innate characteristics, such as instincts and drives. The concept of nurture can be defined as the environmental factors or external stimuli that influence behavior, emotions, and thinking. Biological and physical differences include the human sexual response cycle among men and women.

Evolutionary perspectives on human coupling and/or reproduction, including the sexual strategies theory, provide another perspective on sexuality, as does social learning theory. Socio-cultural aspects of sexuality include historical developments and religious beliefs, including Jewish views on sexual pleasure within the marriage and Christian views on avoidance of sexual pleasures. The study of sexuality also includes human identity within social groups, sexually transmitted infections (STIs/STDs) and birth control methods.

Nature-versus-nurture debate

Main article: Nature versus nurture

Certain characteristics are believed to be innate in humans, although they may be modified by interactions with the physical and social environment. Human sexuality is driven by genetics and mental activity. Normative characteristics, as well as social, cultural, educational, and environmental characteristics of an individual also moderate the sexual drive. The sexual drive affects the development of personal identity and many social activities. There are two well-known theorists who formed the opposing positions in the nature versus nurture debate. Sigmund Freud, a firm supporter of the nature argument, believed that sexual drives are instinctive and viewed sexuality as the central source of human personality. John Locke, on the other hand, believed in the nurture argument, using his theory of the mind being seen as a "tabula rasa" or blank slate, the environment in which one develops drives their sexuality.

Thomas Aquinas

Medieval philosopher Thomas Aquinas held sexuality in accordance with virtues such as temperance and charity not to be evil in itself: "If we suppose the corporeal nature to be created by the good God we cannot hold that those things which pertain to the preservation of the corporeal nature and to which nature inclines, are altogether evil; wherefore, since the inclination to beget an offspring whereby the specific nature is preserved is from nature, it is impossible to maintain that the act of begetting children is altogether unlawful, so that it be impossible to find the mean of virtue therein; unless we suppose, as some are mad enough to assert, that corruptible things were created by an evil god, whence perhaps the opinion mentioned in the text is derived (Sent. iv, D, 26); wherefore this is a most wicked heresy."

The virtue of temperance tempers excess in acts and habits according to Aristotle and Aquinas's virtue ethics, where the aim is not necessarily total abstinence (although Aquinas holds this as easier to achieve), but a perfect mean according to good (i.e. such things as virtue, reason, natural law, Divine Law, and intelligence). Hence, chastity and the habit of virginity, defined as "the continual meditation on incorruption in a corruptible flesh" are the parts of the virtue temperance related to sexuality, and are opposed by excess by lust. Aquinas argues that a reasoned use of sexuality should be according to its end, which is human procreation, again in accordance with charity and other virtues, i.e. "true good":

"A sin, in human acts, is that which is against the order of reason. Now the order of reason consists in its ordering everything to its end in a fitting manner. Wherefore it is no sin if one, by the dictate of reason, makes use of certain things in a fitting manner and order for the end to which they are adapted, provided this end be something truly good. Now just as the preservation of the bodily nature of one individual is a true good, so, too, is the preservation of the nature of the human species a very great good. And just as the use of food is directed to the preservation of life in the individual, so is the use of venereal acts directed to the preservation of the whole human race. Hence Augustine says (De Bono Conjug. xvi): "What food is to a man's well being, such is sexual intercourse to the welfare of the whole human race." Wherefore just as the use of food can be without sin, if it be taken in due manner and order, as required for the welfare of the body, so also the use of venereal acts can be without sin, provided they be performed in due manner and order, in keeping with the end of human procreation."

Aquinas reckons lust to be a "mortal sin" and a "capital vice." The daughters, or consequences, of lust are described as "blindness of mind, thoughtlessness, inconstancy, rashness, self-love, hatred of God, love of this world and abhorrence or despair of a future world." Moreover, as with any "mortal sin," Aquinas reckons that lust destroys the charity, and consequently also the happiness, in humans.

Sigmund Freud

Freud's theory assumed that behavior was rooted in biology. He proposed that instincts are the principal motivating forces in the mental realm, and held that there are a large number of instincts but that they are reduced into two broad groups; Eros (the life instinct), which covers all the self-preserving and erotic instincts, and Thanatos (the death instinct), which covers instincts toward aggression, self-destruction, and cruelty. Freud gave sexual drives a centrality in human life, actions, and behaviors that had not been accepted before his proposal. His instinct theory suggested that humans are driven from birth by the desire to acquire and enhance bodily pleasures, thus supporting the nature debate. Freud successfully redefined the term "sexuality" to make it cover any form of pleasure that can be derived from the human body, raised the notion that the pre-genital zones are primitive areas of preliminary enjoyment preceding sexual intercourse and orgasm. He reasoned that pleasure lowers tension, while displeasure raises it, influencing the sexual drive in humans. His developmentalist perspective was governed by inner forces, especially biological drives and maturation, and his view that humans are biologically inclined to seek sexual gratification demonstrates the nature side of the debate.

John Locke

Locke (1632 – 1704) rejected the assumption that there are innate differences among people, and argued that people are shaped strongly by their social environments, especially by education. He believed that it would be accurate to view a child’s mind as a tabula rasa or blank slate; whatever goes into the mind will come from the surrounding environment. As the person develops, they discover their identity. Locke proposed to follow a child from its birth and observe the changes that time makes, saying that one will find that as the mind, through sensory information, becomes furnished with ideas, it becomes more awake and aware. He said that after some time, the child’s mind begins to know the objects which are most familiar. As the child’s brain develops, he or she begins to know the people and social surroundings of daily life and can then distinguish the known from the unknown. This view supports the nurture side of the debate. Locke believed that there are no natural obstructions that would block the development of children's inherent potential for acting freely and rationally and that everyone is born to become independent beings and benefit from the environment.

Human sexual behavior is different than the sexual behavior of most other animal species, in that it seems to be affected by several factors. For example, while most non-human species are driven to partake in sexual behavior when reproduction is possible, humans are not sexually active just for the sake of reproduction. The environment, culture, and social setting play major roles in the perception, attitudes, and behaviors of sexuality. Sexual behavior is also affected by the inability to detect sexual stimuli, incorrect labeling, or misattribution. This may in turn impede an individual’s sexual performance.

Evolutionary aspects

Sex in private distinguishes humans from bonobos, chimpanzees, and gorillas. Testis and penis size are related to family structure: monogamy or promiscuity, harem, in human, chimpanzee, and gorilla, respectively (see The Third Chimpanzee and Why is Sex Fun? by Jared Diamond). Involvement of the father in education, concealed ovulation, and menopause in women, are quite unique to our species, at least when compared to other hominins. Concealed (or “hidden”) ovulation means that the phase of fertility is not detectable in humans, whereas chimpanzees advertise ovulation by an obvious swelling of the genitals. Women can be partly aware of their ovulation, along the menstrual phases, but men are essentially unable to detect ovulation in women. Most primates have semi-concealed ovulation; thus, one can think that the common ancestor had semi-concealed ovulation, that she transmitted to gorillas, but that later evolved into concealed ovulation in humans and advertised ovulation in chimpanzee (see "Why is Sex Fun?").

Biological and physiological aspects

The biological aspects of humans' sexuality deal with the human reproductive system and human sexual response cycle and the factors that affect these processes. They also deal with the influence of biological factors on other aspects of sexuality, such as organic and neurological responses, heredity, hormonal issues, gender issues, and sexual dysfunction.

Physical anatomy and reproduction

Men and women are anatomically similar except when it comes to the reproductive system and genitalia. Both men and women have different physical mechanisms that enable them to perform sexual acts and procreate. Both men and women react to sexual stimuli in somewhat of the same fashion with only minor differences. Women have a monthly reproductive cycle and the male sperm production cycle is more continuous.

Brain

The brain is the structure that translates nerve impulses from the skin into pleasurable sensations. It controls nerves and muscles used during sexual behavior. The brain regulates the release of hormones which are believed to be the physiological origin of sexual desire. The cerebral cortex, which is the outer layer of the brain and allows for thinking and reasoning is believed to be the origin of sexual thoughts and fantasies. Beneath the cortex is the limbic system, which consists of the amygdala, hippocampus, cingulate gyrus, and septal area. These structures are where emotions and feelings are believed to originate from and are important for sexual behavior.

The hypothalamus is the most important part of the brain for sexual functioning. This is the small area at the base of the brain consisting of several groups of nerve cell bodies that receives input from the limbic system. Studies have shown that within lab animals, destruction of certain areas of the hypothalamus causes complete elimination of sexual behavior. One of the reasons for the importance of the hypothalamus is its relation to the pituitary gland which lies right beneath it. The pituitary gland secretes hormones that are produced in the hypothalamus and itself. The four important sexual hormones secreted are oxytocin, prolactin, follicle-stimulating hormone, and luteinizing hormone. Oxytocin is also known as the “Hormone of Love.” Oxytocin is released in both men and women during sexual intercourse when an orgasm is achieved. It is believed that oxytocin is involved with maintaining close relationships. The hormone is also released in women when they give birth or are breastfeeding. Both prolactic and oxytocin stimulate milk production in women. Follicle-stimulating hormone (FHS) is responsible for ovulation in women by triggering egg maturity and in men it stimulates sperm production. Luteinizing hormone (LH) triggers ovulation which is the release of a mature egg.

Female anatomy and reproductive system

Main article: Human female reproductive system

Women have both external (genitalia) and internal reproductive organs. For the women, their genitalia can be collectively known as the vulva. The vulva includes the mons veneris, labia majora, labia minora, clitoris, vaginal opening, and urethral opening. Women’s genitalia vary in appearance from person to person, differing in size, shape, and color. A woman’s feelings towards her genitalia are directly related to her participation and enjoyment of anything sexual.

External female anatomy

External female genitals

The mons veneris is also known as the "Mound of Venus." This area is the soft layer of fatty tissue overlaying the area where the pubic bone comes together. Following puberty, this area grows in size. It is sensitive to stimulation due to many nerve endings gathering in this area.

The labia (minora and majora) are collectively known as the lips. The labia majora are two elongated folds of skin extending from the mons to the perineum in women. Its outer surface becomes covered with hair after puberty. Labia majora would also be known as the outer lips. In between the labia majora are the labia minora. These two hairless folds of skin meet above the clitoris to form the clitoral hood, which is highly sensitive to touch. The labia minora become engorged with blood during sexual stimulation, causing them to swell and turn bright red or wine colored. Near the anus, the labia minora merge with the labia majora. The labia minora are composed of connective tissues that are richly supplied with blood vessels which cause the pinkish appearance. The purpose of the labia minora is to protect the vaginal and urethral opening by covering them in a sexually unstimulated state. Located at the base of the labia minora are the Bartholin's glands which contribute a few drops of an alkaline fluid to the vagina via ducts which helps to counteract acidity of the outer vagina since sperm cannot live in an acidic environment.

The clitoris is developed from the same embryonic tissue as the penis, but with its glans alone harboring as many or more nerve endings than the human penis, as well as more than any other part of the human body, making the clitoris extremely sensitive to touch. This small, elongated erectile structure has only one known function—sexual sensations. The clitoris is also the main source of orgasm in women. The thick secretions that collect here in the clitoris are called smegma.

The vaginal opening and the urethral opening are only visible when the labia minora are parted. This opening has many nerve endings that make it sensitive to touch. It is surrounded by the bulbocavernosus muscle which is a ring of sphincter muscles that contract and relax. Underneath this muscle and on opposite sides of the vaginal opening are the vestibular bulbs which help the vagina grip the penis by swelling with blood during arousal. Within the vaginal opening, there is something called the hymen which is a thin membrane that partially covers the opening in many virgins. To rupture the hymen is considered to be losing one’s virginity. The urethral opening expels urine from the bladder. This is located below the clitoris and above the vaginal opening. This opening connects to the bladder with the urethra.

The last part of the external organs used for sexual pleasure are the breasts. Western culture is one of the few that find breasts to be erotic. The breasts are the subcutaneous tissues on the front thorax of the female body. Their purpose is to provide milk to a developing infant. They develop during puberty due to an increase in estrogen, and each adult breast consists of 15 to 20 mammary glands, which are milk producing glands. It is the more fatty tissue one has that determines the size of breasts, and heredity plays a huge role in determining size. “A mammary gland is composed of fifteen to twenty irregularly shaped lobes, each of which includes alveolar glands, and a duct (lactiferous duct) that leads to the nipple and opens to the outside. The lobes are separated by dense connective tissues that support the glands and attach them to the tissues on the underlying pectoral muscles. Other connective tissue, which forms dense strands called "suspensory ligaments," extends inward from the skin of the breast to the pectoral tissue to support the weight of the breast. The breasts are really modified sweat glands, which are made up of fibrous tissues and fat that provide support and contain nerves, blood vessels and lymphatic vessels.”

Internal female anatomy

File:Female reproductive system lateral.png

The female reproductive system

The female's internal reproductive organs consist of the vagina, uterus, Fallopian tubes, and ovaries. The vagina is the sheath-like canal in women that extends from the vulva to the cervix. The vagina receives the penis during intercourse and serves as a depository for sperm. This is also known as the birth canal and can expand to 10 centimeters during labor and delivery. The vagina is located behind the bladder but in front of the rectum. The vagina is normally collapsed, but during sexual arousal it opens, lengthens, and produces lubrication, which allows the penis to be inserted. The vagina has three layered walls, and is a self-cleaning organ with natural important bacterium within it to keep the production of yeast down. The G-Spot, named after the German doctor who first reported it in 1950, may be located in the front wall of the vagina and may cause orgasms. This area can vary in size and location from woman to woman, or be non-existent in some women, and various researchers dispute its structure, existence or hypothesize that it is an extension of the clitoris.

The uterus is also known as the womb; a hollow, muscular organ where a fertilized egg, called a zygote, will implant itself and grow into a fetus. The uterus lies in the pelvic cavity behind the bladder, in front of the bowel, and above the vagina. Normally, it is positioned in a ninety-degree angle tilting forward, although in about twenty percent of women it tilts backwards. The uterus consists of three layers with the innermost layer being the endometrium. The endometrium is where the egg is implanted. During ovulation, this thickens up for implantation, but if implantation does not occur, it is sloughed off during menstruation. The cervix is the narrow end of the uterus. The broad part of the uterus is the fundus.

The Fallopian tubes are the passageways that an egg travels down to the uterus during ovulation. These extend about four inches from both sides of the uterus. There are finger like projections at the end of the tubes that brush the ovaries and pick up the egg once it is released. The egg then travels for about three to four days down to the uterus. “After sexual intercourse, sperm swim up this funnel from the uterus. The lining of the tube and its secretions sustain both the egg and the sperm, encouraging fertilization and nourishing the egg until it reaches the uterus. If an egg splits in two after fertilization, identical twins are produced. If separate eggs are fertilized by different sperm, the mother gives birth to non-identical or fraternal twins."

The ovaries are the female gonads, and they are developed from the same embryonic tissue as the male gonads (testicles). These are suspended by ligaments and are the source where the egg or ova are stored and developed before ovulation. The ovaries are also responsible for producing female hormones: progesterone and estrogen. Within the ovaries, each egg is surrounded by other cells and contained within a capsule called a primary follicle. At puberty, one or more of these follicles are stimulated to mature on a monthly basis. Once matured these are now called Graafian follicles. “The female, unlike the male, does not manufacture the sex cells. A girl baby is born with about 60,000 of these cells.” Only about 400 eggs in a women’s lifetime will mature.

A female's ovulation is based on a monthly cycle with the fourteenth day being the most fertile. Days five through thirteen are known as the Preovulatory stages. During this stage, the pituitary gland in the brain secretes Follicle-stimulating hormone (FSH). Then a negative feedback loop is enacted when estrogen is secreted to inhibit the release of FSH. This estrogen thickens the endometrium of the uterus. Luteinizing Hormone (LH) surge triggers ovulation. Day fourteen, ovulation, the LH surge causes a Graafian follicle to surface the ovary. Once the follicle ruptures, the ripe ovum is expelled into the abdominal cavity where the fallopian tubes pick up the ovum with the fimbria. The cervical mucus changes to aid in the movement of sperm. Days fifteen to twenty-eight, the Post-ovulatory stage, the Graafian follicle that once held the ovum is now called the corpus luteum, and it now secretes estrogen. Progesterone increases inhibiting LH release. The endometrium thickens to get ready for implantation, and the ovum travels down the Fallopian tubes to the uterus. If the egg does not become fertilized and does not implant menstruation begins. Days one to four, menstruation, estrogen and progesterone decreases and the endometrium starts thinning. Now the endometrium is sloughed off for the next three to six days. Once menstruation ends the cycle begins again with an FSH surge from the pituitary gland.

Male anatomy and reproductive system

Main article: Human male reproductive system

Men also have both internal and external (genitalia) structures that are responsible for procreation and sexual intercourse. Men produce their sperm on a cycle, but unlike the female’s ovulation cycle, the male sperm production cycle is constantly producing millions of sperm daily.

External male anatomy

External male genitals

The male genitalia are the penis (which has both internal and external structures) and the scrotum (holds the testicles). The penis's purpose is for sexual intercourse and is a passageway for sperm and urine. An average sized unstimulated penis is about 3.75 inches in length and 1.2 inches in diameter. When erect on average, men are most between 4.5 to 6 inches in length and 1.5 inches in diameter; 4.5 inches in circumference. The penis's internal structures consist of the shaft, glans, and the root.

The shaft of the penis consists of three cylinder-shaped bodies of spongy tissue filled with tiny blood vessels, which run the length of the organ. Two of these bodies lie side by side in the upper portion of the penis called corpora cavernosa. The third is a tube which lies centrally beneath the others and expands at the end to form the tip of the penis (glans) called the corpus spongiosum. The raised rim at the border of the shaft and glans is called the corona. The urethra runs through the shaft so that sperm and urine have a way out the body. The root consists of the expanded ends of the cavernous bodies, which fan out to form the crura, and attach to the pubic bone and the expanded end of the spongy body also known as the bulb. The root is also surrounded by two muscles: bulbocavernosus muscle and ischiocavernosus muscle which aid in urination and ejaculation. The penis has a foreskin that usually covers the glans, and in many cultures, is removed at birth in a controversial procedure called circumcision. Circumcision is one of the oldest forms of body modification known to exist. The second external structure is the scrotum. Here the testicles are held away from the body so that sperm can be produced in an environment several degrees lower than normal body temperature. Sweat glands are also located in this region to aid in temperature control.

Internal male anatomy

File:Male anatomy.png

The male reproductive system

Males also have internal reproductive structures as well, and these consist of the testicles, the duct system, the prostate and seminal vesicles, and the Cowper’s gland.

The testicles are the male gonads. This is where sperm and male hormones (androgens) are produced. Millions of sperm are produced daily in several hundred seminiferous tubules that altogether measure over a quarter of a mile. Cells called the Leydig cells or interstitial cells of Leydig are between the tubules and produce hormones. The hormones that are produced are called androgens, and they consist of testosterone and inhibin. The testicles are held by the spermatic cord, which is a tubelike structure which contains blood vessels, nerves, the vas deferens, and a muscle that helps to raise and lower the testicles in response to temperature changes and sexual arousal in which the testicles are drawn closer to the body.

The next internal structure is the four part duct system that transports sperm. The first part of this system is the epididymis. The seminiferous tubules are the testicles converging to form coiled tubes that are felt at the top and back of each testicle. Each tubule uncoiled is about twenty feet long. The second part of the duct system is the vas deferens. The vas deferens is also known as “ductus deferens,” and is a muscular tube that begins at the lower end of the epididymis. The vas deferens also passes upward along the side of the testicles to become part of the spermatic cord. The expanded end is the ampulla which stores sperm before ejaculation. The third part of the duct system are the ejaculatory ducts which are one inch long paired tubes that pass through the prostate gland. This is where semen is produced. The prostate gland is a solid, chestnut-shaped organ that surrounds the first part of the urethra (tube which carries the urine and semen and the fourth part of the duct system) in the male.

The prostate gland and the seminal vesicles help produce seminal fluid that gets mixed with sperm to create semen. The prostate gland lies under the bladder, in front of the rectum. It consists of two main zones: the inner zone which produces secretions to keep the lining of the male urethra moist and the outer zone which produces seminal fluids to facilitate the passage of semen. The seminal vesicles secrete fructose for sperm activation and mobilization, prostaglandins to cause uterine contractions which aids in movement through the structure, and bases which help neutralize the acidity of the vagina because sperm cannot survive in an acidic environment. The last internal structure is the Cowper’s glands, or bulbourethral glands, which are two pea sized structures beneath the prostate. These structures

Sexual response cycle

The sexual response cycle is a model that describes the physiological responses that take place in men and women during sexual activity. This model was created by William Masters and Virginia Johnson. According to Masters and Johnson, the human sexual response cycle consists of four phases: excitement, plateau, orgasm, and resolution. The excitement phase is the phase in which one attains the intrinsic motivation to pursue sex. The plateau phase sets the stage for orgasm. Orgasm may be more biological for men and more psychological for women. Orgasm is the release of tension, and the resolution period is the unaroused state before the cycle begins again.

The male sexual response cycle starts out in the excitement phase where two centers in the spine are responsible for an erection. Vasoconstriction begins in the penis, the heart rate increases, scrotum thickens, spermatic cord shortens, and the testicles become engorged in blood. The second phase, plateau, the penis increases in diameter, the testicles become even more engorged, and the Cowper’s glands secrete preseminal fluid. The third stage, orgasm, during which rhythmic contractions occur every 0.8 seconds, consists of two phases in men. The first phase of orgasm is the emission phase in which contractions of the vas deferens, prostate, and seminal vesicles encourage ejaculation which is the second phase of orgasm. This phase of orgasm is called the expulsion phase and this phase cannot be reached without an orgasm. Finally, the resolution phase is when the male is now in an unaroused state which consists of a refractory period (rest period) before the cycle can begin. This rest period may increase with a man’s age.

The female sexual response begins with the excitement phase which can last from several minutes to several hours. Characteristics of this phase include increased heart and respiratory rate and an elevation of blood pressure. Flushed skin or blotches of redness may occur on the chest and back; breasts increase slightly in size and nipples may become hardened and erect. The onset of vasocongestion results in swelling of the woman's clitoris and labia minora and the woman's vagina begins to swell. The muscle that surrounds the vaginal opening grows tighter and her uterus elevates and grows in size. The vaginal walls begin to produce a lubricating liquid. The second phase, called the plateau phase, is characterized primarily by the intensification of all of the changes begun during the excitement phase. The plateau phase extends to the brink of orgasm, which initiates the resolution stage, the reversal of all of the changes begun during the excitement phase. During the orgasm stage the heart rate, blood pressure, muscle tension, and breathing rates reach maximum peaks. The pelvic muscle near the vagina, the anal sphincter and the uterus contract. While muscle contractions in the vaginal area create a high level of pleasure, all orgasms are centered in the clitoris, whether they result from direct manual stimulation applied to the clitoris or indirect pressure resulting from the thrusting of penis during sexual intercourse.

Sexual dysfunction and sexual problems

Men and women have many sexual problems which frequently arise because of other problems within a relationship or simply because of individual differences. These differences consist of differences in expectations, assumptions, desire, preferred behaviors, and relationship conflicts. Although these differences create sexual problems in both men and women, problems among men and women are different. The World Health Organization’s International Classifications of Diseases defines sexual problems as “the various ways in which an individual is unable to participate in a sexual relationship as he or she would wish.” Sexual disorders, according to the DSM-IV-TR, are disturbances in sexual desire and psycho-physiological changes that characterize the sexual response cycle and cause marked distress, and interpersonal difficulty. There are four major categories of sexual problems: desire disorders, arousal disorders, orgasmic disorders, and sexual pain disorders.

1. Hypoactive sexual desire
   1. Low sexual drive
   2. Occurs at the excitement phase
2. Sexual aversion
   1. Anticipation of any kind of sexual interactions causes great anxiety
3. Sexual arousal disorder
   1. In men, erectile dysfunction
   2. In women, the difficulty of becoming aroused
4. Orgasmic disorders
   1. In men, premature ejaculation and ejaculatory incompetence
   2. In women, the inability to have an orgasm
5. Hypersexuality (sexual addiction)
6. Sexual pain disorders
   1. In men, four different disorders:
      1. Dyspareunia (pain during intercourse due to a physical problem)
      2. Post-ejaculatory syndrome (pain in the genitals during or after orgasm)
      3. Priapism (prolonged erection)
      4. Coital cephalalgia (migraine headaches during and after orgasm)
   2. In women, three different disorders:
      1. Dyspareunia (recurrent genital pain during intercourse)
      2. Vaginismus (vagina involuntarily closes)
      3. Noncoital sexual pain disorder (genital pain due to arousal)

Psychological aspects

Sigmund Freud with daughter Anna

Sexuality in humans generates profound emotional and psychological responses. Some theorists identify sexuality as the central source of human personality. Psychological studies of sexuality focus on psychological influences that affect sexual behavior and experiences. Early psychological analyses were carried out by Sigmund Freud, who believed in a psychoanalytic approach. He also conjectured the concepts of erogenous zones, psychosexual development, and the Oedipus complex, among others.

Behavior theorists such as John B. Watson and B. F. Skinner examine the actions and consequences and their ramifications. These theorists would, for example, study a child who is punished for sexual exploration and see if they grow up to associate negative feelings with sex in general. Social-learning theorists use similar concepts, but focus on cognitive activity and modeling.

Gender identity is a person's own sense of identification as female, male, both, neither, or somewhere in between. The social construction of gender has been discussed by a wide variety of scholars, Judith Butler notable among them. Recent contributions consider the influence of feminist theory and courtship research.

Sexual behavior and intimate relationships are strongly influenced by a person's sexual orientation. Sexual orientation refers to your degree of emotional and physical attraction to members of the opposite sex, same sex, or both sexes. Heterosexual people are attracted to the members of the opposite sex. Homosexual people are attracted to people of the same sex. Those who are bisexual are attracted to both men and women.

Before the High Middle Ages, homosexual acts appear to have been ignored or tolerated by the Christian church. During the 12th century however, hostility toward homosexuality began to spread throughout religious and secular institutions. By the end of the 19th century, homosexuality was viewed as a pathology. Havelock Ellis and Sigmund Freud adopted more accepting stances. Ellis argued that homosexuality was inborn and therefore not immoral, that it was not a disease, and that many homosexuals made significant contributions to society. Freud believed all human beings as capable of becoming either heterosexual or homosexual; neither orientation was assumed to be innate. Freud claimed that a person’s orientation depended on how the Oedipus complex was resolved. He believed that male homosexuality resulted when a young boy had an authoritarian, rejecting mother and turned to his father for love and affection and later to men in general. He believed female homosexuality developed when a girl loved her mother and identified with her father and became fixated at that stage.

Freud and Ellis thought homosexuality resulted from reversed gender roles. This view is reinforced today by the media’s portraying male homosexuals as effeminate and female homosexuals as masculine. Whether a person conforms or does not conform to gender stereotypes does not always predict sexual orientation. Society believes that if a man is masculine he is heterosexual, and if a man is feminine he must be homosexual. There is no strong evidence that a homosexual or bisexual orientation must be associated with atypical gender roles. Today, homosexuality is no longer considered to be a pathology. In addition, many factors have been linked to homosexuality including: genetic factors, anatomical factors, birth order, and hormones in the prenatal environment.

Other than the need of extending one's family tree, there are many other reasons people have sex. According to one study conducted on college students (Meston & Buss, 2007), the four main reasons for sexual activities are: physical attraction, as a means to an end, to increase emotional connection, and to alleviate insecurity.

Sexuality and age

Child sexuality

Main article: Child sexuality

In the past, children were often assumed not to have sexuality until later development. Sigmund Freud was one of the first researchers to take child sexuality seriously. His ideas, such as psychosexual development and the Oedipus conflict, have been highly debated but regardless, acknowledging the existence of child sexuality was a huge milestone. Freud gave sexual drives an importance and centrality in human life, actions, and behavior arguing that sexual drives exist and can be discerned in children from birth. He explains this in his theory of infantile sexuality, and claims that sexual energy (libido) is the single most important motivating force in adult life. Freud wrote about the importance of interpersonal relationships to ones sexual and emotional development. From the initial days of life, the mother's connection to the infant has an effect on the infant's later capacity for pleasure and attachment. Freud described two currents of emotional life in all of us: an affectionate current, including our bonds with the important people in our lives, and a sensual current, including our wish to gratify sexual impulses. During adolescence, a young person tries to integrate these two emotional currents. This is a difficult task and the risks are many. There are numerous inner conflicts and failures of development that may keep a person repeating immature sexual patterns; this is evident in much that we see on the news. The real challenge is to bring about a convergence of the two currents; the affectionate and the sensual. The sexual over excitement often characteristic of adolescent experimentation is not adaptive in a grown adult.

Freud's work led him to establish the stages of psychosexual development where he describes infantile sexuality through steps. From the moment of birth an infant is driven in their actions by the desire for bodily and sexual pleasure. This is seen by Freud as the desire to release mental energy. At first, infants gain such release, and derive pleasure from the act of sucking. Freud terms this the oral stage of development. It’s followed by a stage in which the center of pleasure or energy release is the anus, mainly in the act of defecation. This is termed the anal stage. Then, the young child develops an interest in its genitalia as a site of pleasure known as the phallic stage. According to Freud, the child then develops a deep sexual attraction for the parent of the opposite sex, and a hatred of the parent of the same sex. This is known as the Oedipus complex. However, this gives rise to socially derived feelings of guilt in the child, who eventually recognizes that it can never supersede the stronger parent. A male child also perceives himself to be at risk, he fears that if he persists in pursuing the sexual attraction for his mother, he may be harmed by the father. Both the attraction for the mother and the hatred are usually repressed, and the child typically resolves the conflict of the Oedipus complex by coming to identify with the parent of the same sex. This happens at the age of five, whereupon the child enters a latency period in which sexual motivations become much less pronounced. This lasts until puberty when mature genital development begins and the pleasure drive refocuses around the genital area. Freud believed that this is the progression inherent in normal human development, and is to be observed beginning at the infant level. The instinctual attempts to satisfy the pleasure drive are frequently checked by parental control and social influencing. For the child, the developmental process is in essence a movement through a series of conflicts. The successful resolution of these conflicts is crucial to adult mental health. Many mental illnesses, particularly hysteria, Freud held, can be traced back to unresolved conflicts experienced at this stage, or to events which otherwise disrupt the normal pattern of infantile development. For example, homosexuality is seen by some Freudians as resulting from a failure to resolve the conflicts of the Oedipus complex, particularly a failure to identify with the parent of the same sex; the obsessive concern with washing and personal hygiene which characterizes the behavior of some neurotics is seen as resulting from unresolved conflicts or repressions occurring at the anal stage.

Alfred Kinsey also examined child sexuality in his Kinsey Reports. Children are naturally curious about their bodies and sexual functions. For example, they wonder where babies come from, they notice the differences between males and females, and many engage in genital play (often mistaken for masturbation). Child sex play includes exhibiting or inspecting the genitals. Many children take part in some sex play, typically with siblings or friends (playing doctor). Sex play with others usually decreases as children go through their elementary school years, yet they still may possess romantic interest in their peers. Curiosity levels remain high during these years, but it is not until adolescence that the main surge in sexual interest occurs.

Sexuality in late adulthood

Main article: Sexuality in older age

Adult sexuality originates in childhood. However, like many other human capacities, sexuality is not fixed, but matures and develops. A common stereotype suggests that people tend to lose interest in and ability to engage in sexual acts once they reach late adulthood. This stereotype is reinforced by Western pop culture, which often ridicules older adults that try to engage in sexual activities. Men are shown suffering heart attacks from over-excitement, and women are depicted as grateful if anyone shows an interest in them. The term "dirty old man" is applied to older men who show an interest in sex beyond a level the speaker considered appropriate . The language for older women, by contrast, is sexless, and older women are portrayed as sexually unattractive and undesirable. Sexuality, however, is similar to most other aspects of aging. Age does not necessarily change the need or desire to be sexually expressive or active. If a couple has been in a long-term relationship, the frequency of sexual activity may decrease, but not necessarily their satisfaction with each other. Many couples find that the type of sexual expression may change, and that with age and the term of relationship there is increased intimacy and love. If sex and sexual intimacy are important aspects in one's life during young and middle adulthood they will continue to be factors in older adulthood.

Physical changes do, however, occur with age. One aspect of aging that is particular to a woman's experience is the menopause. This process, which occurs toward the late forties or early fifties, is dependent on a woman’s biological makeup. Common signs of the menopause include lengthening or shortening of the menstrual cycle and blood loss that becomes either heavier or lighter than usual. Hot flashes may occur up to two years prior to menopause and continue for several years after. Night sweats are a common symptom for women who are approaching menopause. Loss of muscle tone in the urinary tract may cause more frequent urination, while some women become more prone to urinary tract infections. Skin may also become more dry or oily than usual. Hormonal changes may also be the reason for vaginal dryness, joint pain and abdominal weight gain. Many women are made to feel that because they are no longer able to reproduce, they are no longer able to be sexually active. Some women may experience a decline in sexual desire because of the decline in production of the hormone estrogen. However, many other women report an increase in desire and activity. This is likely because there is no longer a concern about pregnancy, and children are generally self-sufficient; postmenopausal woman may even be more assertive in expressing their needs.

Although men do not experience an equivalent process to the menopause, they may experience the male climacteric. This occurs between the ages of 35 and 60. Although remaining fertile, climacteric men may feel unsatisfied with their achievements and lifestyles. They may also experience a range of unpleasant emotions and physical symptoms that are linked to the aging process. A gradual decrease in testosterone production may cause physical symptoms such as a lack of energy, erectile dysfunction, and muscle deterioration. These changes may also coincide with weakening health in the heart, prostate, kidneys, hearing and digestive systems, due to aging. One out of every four men between the ages of 65 to 80 has severe problems getting or keeping erections, and this percentage increases with men over 80 years of age. These changes can be accommodated by increased manual stimulation and other modes of sexual expression in addition to normal intercourse. Drugs are also available to treat erectile dysfunction.

Two other factors that may have an increasing impact on sex and sexual activity as an individual ages are partner availability and health problems, including the effects of medication. A recent interview study involving 3,000 adults between the ages of 57 and 85 found that the percentage of sexually active older adults is higher for those that are in good health than those in poor health. Older women may also be less sexually active as a result of outliving their partners or men's tendency to marry younger women. Older adults who engage in sexual activity, intimacy, and companionship tend to be more satisfied with life. For older women, partner availability is a particularly serious issue. Women outnumber men by increasingly larger numbers as they age. Many divorced, widowed, or never-married older women may find themselves alone and looking more towards masturbation for sexual gratification.

Sociocultural aspects

Women's liberation demonstration, 1970

Human sexuality can also be understood as part of the social life of humans, governed by implied rules of behavior and the status quo. This focus narrows the view to groups within a society. The socio-cultural context of society places major influences on and form social norms, including the effects of politics and the mass media. In the past people fought for their civil rights, and such movements helped to bring about massive changes in social norms – examples include the sexual revolution and the rise of feminism.

The link between constructed sexual meanings and racial ideologies has been studied in the past. It is found sexual meanings are constructed to maintain racial-ethnic-national boundaries, by denigration of "others," and regulation of sexual behavior within the group. "Both adherence to and deviation from such approved behaviors, define and reinforce racial, ethnic, and nationalist regimes."

The age and manner in which children are informed of issues of sexuality is a matter of sex education. The school systems in almost all developed countries have some form of sex education, but the nature of the issues covered varies widely. In some countries (such as Australia and much of Europe) "age-appropriate" sex education often begins in pre-school, whereas other countries leave sex education to the pre-teenage and teenage years. Sex education covers a range of topics, including the physical, mental, and social aspects of sexual behavior. Where one is geographically placed also plays a role in when society feels it is appropriate for a child to learn about sexuality. In the United States, sexuality is on the “hush-hush” or is unspoken of which happens to limit sources of sexual knowledge. According to TIME magazine and CNN, 74% of teenagers reported that their major source of sexual information were their peers and the media compared to only 10% naming their parents or a sex education course; therefore society makes a huge impact on people’s views when it comes to the acceptable and unacceptable behaviors and attitudes towards sexuality. Society’s views on sexuality have many influences from the past and the present. Even religion and philosophy make an impact. One theorist, Vygotsky states that a child’s development cannot be understood only by the individual alone. The only way to truly understand development is by looking at the individual and the environment or external social world in which the development is occurring.

Religious sexual morality

Main article: Religion and sexuality

Most world religions have sought to address the moral issues that arise from people's sexuality in society and in human interactions. Each major religion has developed moral codes covering issues of sexuality, morality, ethics etc., which have sought to guide people's sexual activities and practices. The influence of religion on sexuality is especially apparent in the long debated issue of gay marriage versus civil union.

When it comes to Judaism it is said that sex is sacred between man and women, within marriage, and should be enjoyed. Celibacy is sinful. Actually, the Jewish do not believe that sex is shameful, sinful, or obscene, although the Jewish faith emphasizes that sexual desire should be controlled and channeled only to be satisfied at the proper time, place, and manner, between husband and wife, out of mutual love and desire for one another. This means that all sexual contact is permissible only within marriage because it is believed that all sexual contact leads to intercourse; therefore sex requires commitment and responsibility. The primary purpose of sex according to the Jewish is to reinforce the marital bond and to procreate making any sexual act permissible as long as it does not involve ejaculation outside the vagina. Sex is the right of the woman, not the man and it is should only be experienced in times of joy because it is a selfish personal satisfaction that must be pleasurable for both parties. Men cannot force women to have sex, and women cannot take away sex as punishment because it is an offense to use sex to manipulate or as a weapon. Finally, sex cannot be experienced while intoxicated or quarreling.

Traditionally, Christianity has viewed human sexuality as primarily though not exclusively aimed at reproduction and as tainted by concupiscence after the Fall. Saint Paul spoke of the flesh as at war with the spirit and struggled to control it, though he saw the body itself as holy and a temple of the Holy Spirit (I Cor 6:19). He stated that a celibate lifestyle was preferable for serving God undistracted, which was later cited as a reason for priests having to give up sex and marriage. Saint Augustine believed that sex was only justified in marriage with a view toward procreation, and that when aimed exclusively at pleasure it was tainted by sin. Saint Augustine speaks of the three goods of marriage, the good of fidelity (fidei), of offspring (prolis), and of the sacramental bond (sacramenti).

The Bible states within the first commandment to procreate, but the misconception about sex being shameful or sinful is contradicted. In the book of Genesis 2:24-25, it states that a husband must stick to his wife and they shall become one flesh. And the man and his wife were both naked and were not ashamed. The becoming one flesh is the sexual act which according to this, does not lead into shame. On the other hand, both husband and wife are supposed to be submissive sexually to their partner, no longer having authority over their own bodies, and cannot deny each other sex in order to refrain from satisfying in temptation from out the marriage since fidelity (faithfulness to a sexual partner) is important. The bible may permit sexual activity within a marriage between man and women; it is a sin to engage in homosexuality, bestiality (sexual relations with animals), incest (sexual relations within the immediate family structure), fornication (sex outside marriage), adultery (cheating on husband or wife), rape, and viewing pornography. It is believed that those who are sexually immoral are separated from God and will not share in God’s inheritance upon death. To engage in any of these sinful sexual activities in the past, punishment was death.

The Catholic Church teaches that sexuality is "noble and worthy" but that it must be used in accordance with natural law. For this reason, all sexual activity must occur in the context of a marriage between a man and a woman and must not be divorced from the possibility of conception. All forms of sex not open to conception are considered intrinsically disordered and sinful, such as any sex with contraceptives, autosexual activity (e.g. masturbation), and homosexual acts. Recent currents of Catholic thought, such as John Paul II's Theology of the Body, have placed special emphasis on the dignity and beauty of human sexuality, calling it a special gift of God that is preserved and respected by reserving it for marriage. Sex is sanctified by the rebirth of Christ. It helps us to grow and create bonds of love.

Within the Islamic faith, sexual desire is considered to be a natural urge that should not be suppressed, although, the concept of free sex is not accepted; therefore these urges should be fulfilled responsibly. Marriage is considered to be a good deed and it does not hinder spiritual wayfaring. The term used for marriage within the Quran is nikah which literally means sexual intercourse. Although, Islam was sexually restrained, the Islamic faith emphasized sexual pleasure within marriage. It is acceptable for a man to have more than one wife, but he must take care of that wife physically, mentally, emotionally, financially, and spiritually. They oppose celibacy and monasticism (withdrawing from society to devote one’s self to prayer, solitude, and contemplation).

The views on sexuality in Hinduism emphasizes that sex is only appropriate between husband and wife in which satisfying sexual urges through sexual pleasure is an important duty of marriage. Any sex before marriage is considered to interfere with their intellectual development, especially between birth and the age of 25 which is said to be brahmacharya; therefore, this should be avoided. Kama (sensual pleasures) is one of the four purusharthas or aims of life (dharma, artha, kama, and moksha). One of the sacred texts which happen to be popular within Western culture, the Kama Sutra, was created by the Hindus as manual for love making in marriage. This text emphasizes pleasure being the aim of intercourse and even goes in depth about homosexual desires which are believed to be the same as heterosexual desires. Even within Hindu temples (places of worship) there were depictions of sexuality within the sculptures. Such temples are at Khajuraho and Konarak, but due to colonialism, Hindus became more rigid in their views about sexuality, and then internalized Victorian ideals of heterosexual monogamy.

Buddhism emphasizes the "Middle Way," which is never reaching the extremes. According to this religion, moderation in everything is key to enlightenment or nirvana; therefore, human sexuality should fall in the middle on a continuum from extreme Puritanism to extreme permissiveness. Buddhist also emphasize kama which is a sign that their basis of belief uses Hinduism as their foundation. But all in all, Buddhism does not have an specific rules to break that has horrible consequences as other religions do because Buddhists do not believe in sin, there is only the skilled and unskilled, and the feeling of pleasure is neither.

Sexuality in history

Main article: History of human sexuality

The prehistoric Venus of Willendorf

Min: the ancient Egyptian god of fertility

Sexuality has always been a vital part of the human existence and in societies from the long hunting and gathering phases of history to the rise of agriculture, the long centuries of the agricultural period of history, as well as during modern times (44). For all civilizations throughout time, there have been a few common, special characteristics of how sexuality was managed through sexual standards, representations, and behavior. Art and artifacts from past eras help portray human’s perceptions of sexuality throughout time.

Before the rise of agriculture there were groups of hunter/gatherers (H/G) or nomads inhabiting the world. Within these groups, some implications of male dominance existed, but there were also ample signs that women were active participants in sexuality with bargaining power of their own. These H/G groups had less restrictive sexual standards that emphasized sexual pleasure and enjoyment, but with definite rules and constraints. Some underlying continuities or key regulatory standards contended with the tension between recognition of pleasure, interest, and the need, for the sake of social order and economic survival. H/G groups also place high value on certain types of sexual symbolism. Two common tensions of H/G societies are expressed in their art which emphasizes male sexuality and prowess with equally common tendencies to blur gender lines in sexual matters. Some examples of these male dominated portrayals is the Egyptian creation myth when the sun god Atum masturbates in the water creating the Nile River, or in the Sumerian myth of the Gods’ semen filling the Tigris.

Once agricultural societies emerged, the sexuality framework shifted in many ways that persist for many millennia in much of Asia, Africa, Europe, and parts of the Americas. One common characteristic that became new to these societies was the collective supervision of sexual behavior due to the population increases and more concentrated communities due to urbanization. It was a normal event for a child to witness parents having sex because many parents shared the same sleeping quarters with other relatives. Also, due to landownership, determining a child’s paternity became important, and society became patriarchal in family life. These changes in sexual ideology were used to try to control female sexuality and to differentiate standards by gender. With these ideologies, sexual possessiveness and increases in jealousy emerged. With the domestication of animals, new opportunities for bestiality (sex with animals) flourished. Mostly males performed these types of sexual acts and many societies acquired firm rules against it. These acts also explain the many depictions of the half-man, half-animal mythical creatures, and the sports of gods and goddesses with animals. While still holding onto earlier precedents of earlier civilizations, each classical civilization established a somewhat distinctive approach to gender, artistic expression of sexual beauty, and to particular behaviors such as homosexuality. Some of these distinctions are portrayed in sex manuals which were also common among these civilizations. These civilizations consist of China, Greece/Rome, Persia, and India, and each has their own history in the sexual world.

During the 18th and 19th centuries, during the beginning of the industrial revolution, many changes in sexual standards have occurred. New dramatic artificial birth control devices are introduced such as the condom and diaphragm. Doctors started claiming a new role in sexual matters urging that their advice was crucial to sexual morality and health. A significant new pornographic industry blossomed, and Japan adopted its first ever laws against homosexuality. On the other hand, in western societies, the definition of homosexuality is constantly changing, and western influence on others is increasing in strength. New contacts created serious issues around sexuality and sexual traditions. There were also major shifts in sexual behavior. During this period, the ages at which puberty starts to decrease, so a new focus on adolescence as a time of sexual confusion and danger emerges. Finally, there was a new focus on the purpose of marriage being for love rather than just economics and reproduction.

With regard to other modern advances, Alfred Kinsey initiated the modern era of sex research. He collected data by giving questionnaires to his students at Indiana University, but then switched to personal interviews interested in male and female sexual behaviors. Kinsey and his colleagues sampled a total of 5,300 men and 5,940 women. His findings found that most people masturbate, that many engaged in oral sex, women are capable of having multiple orgasms, and that many men had had some type of homosexual experience in their lifetime. Many believe that he was the major influence in changing 20th century attitudes about sex, and Kinsey Institute for Research in Sex, Gender, and Reproduction at Indiana University continues to be a major center for the study of human sexuality. Before William Masters, a physician, and Virginia Johnson, a behavioral scientist, the study of anatomy and physiological studies of sex was still limited to experiments with lab animals. Masters and Johnson started to directly observe and record the physical responses in humans that are engaged in sexual activity under laboratory settings. They covered 10,000 episodes of sexual acts consisting of 312 men and 382 women. This led to methods of treating clinical problems and abnormalities. Masters and Johnson opened the very first sex therapy clinic in 1965. In 1970, they described their therapeutic techniques in their book Human Sexual Inadequacy.

Sexuality of today is not only influenced by human ancestry or religions. Sexuality of today is also influenced by the internal commercial society within societies—mainly western. According to a Time Magazine/CNN survey, 74% of teenagers said that friends and television were their main sources of sexual education. The fact that the average American child spends six to eight hours a day watching, listening to, or reading some form of media explains their reasoning behind these findings. In addition to television, contemporary women's magazines contain a number of scripts about sexual relationships and women's sexual roles that research has shown to have both empowering and problematic effects on women's developing sexual identities and sexual attitudes.

Sexual behavior

General activities and health

Main article: Human sexual activity

See also: Sexual intercourse § Health effects, and Sexually active life expectancy

Human sexual behavior, driven by the desire for pleasure, encompasses the search for a partner or partners, interactions between individuals, whether physical or emotional intimacy, or sexual contact that may lead to foreplay, masturbation and ultimately orgasm.

Human sexual activity, or human sexual practice or human sexual behavior, is the manner in which humans experience and express their sexuality. People engage in a variety of sexual acts from time to time, and for a wide variety of reasons. Sexual activity normally results in sexual arousal and physiological changes in the aroused person, some of which are pronounced while others are more subtle. Sexual activity also includes conduct and activities which are intended to arouse the sexual interest of another, such as strategies to find or attract partners (mating and display behavior), and personal interactions between individuals, such as flirting and foreplay.

Human sexual activity has sociological, cognitive, emotional, behavioral and biological aspects, including personal bonding and shared emotions during sexual activity and physiological processes such as the reproductive system, the sex drive and sexual intercourse and sexual behavior in all its forms.

In humans, sexual intercourse and sexual activity in general have been reported as producing health benefits as varied as improved sense of smell, stress and blood pressure reduction, increased immunity, and decreased risk of prostate cancer. Sexual intimacy, as well as orgasms, increases levels of the hormone oxytocin, also known as "the love hormone", which helps people bond and build trust. A long-term study of 3,500 people between 30 and 101 by clinical neuropsychologist David Weeks, MD, head of old age psychology at the Royal Edinburgh Hospital in Scotland, found that "sex helps you look between four and seven years younger", according to impartial ratings of the subjects' photos. Exclusive causation, however, is unclear, and the benefits may be indirectly related to sex and directly related to significant reductions in stress, greater contentment, and better sleep that sex promotes.

In contrast to its benefits, sexual intercourse can also be a disease vector. There are 19 million new cases of sexually transmitted diseases (STD) every year in the U.S., and worldwide there are over 340 million STDs a year. More than half of all STDs occur in adolescents and young adults aged 15–24 years. At least one in four U.S. teenage girls has a sexually transmitted disease. In the U.S., about 30% of 15–17-year old adolescents have had sexual intercourse, but only about 80% of 15–19-year old adolescents report using condoms for their first sexual intercourse. More than 75% of young women age 18–25 years felt they were at low risk of acquiring an STD in one study.

Birth control

Main article: Birth control

The birth control pill was introduced in 1960 however, until recently condoms and other birth control options that did not require a visit to the doctor were kept behind the counter in drugstores. This inhibited many people from purchasing them. Today, there are numerous contraceptive devices for males as well as females that are sold openly.

1. Relatively Ineffective Methods
   1. Withdrawal (coitus interruptus): One of the most popular ways in which young people try to avoid pregnancy. This method involves the man withdrawing his penis just before reaching orgasm and ejaculating outside his partner’s vagina.
   2. Douching: Some women believe douching is an effective method because it washes out the contents of the vagina (doing it after sex would get rid of sperm). Many do not know that no matter how rapidly a woman douches after sex some sperm have already traveled into the cervix.
   3. Lactational amenorrhea (breast-feeding): When a woman is breast-feeding the sucking response of the baby on her nipple inhibits the pituitary from releasing FSH and LH. This prevents ovulation and normal menstrual cycles.
2. Fertility awareness methods
   1. Calendar method: This method has been promoted by the Catholic Church as a morally acceptable form of family planning. The calendar method is based on 3 assumptions:

• Ovulation occurs 14 days before a woman’s menstrual cycle, plus or minus 2 days
• Sperm can remain alive for up to 3 days
• The ovum can be fertilized 24 hours after it has been released from the ovary

Using those 3 concepts, a woman with a regular cycle can count backwards from the first day of her period to figure out when she will be ovulating and avoid having sex during that time in the following month.

1. 1. Basal body temperature method: This method involves recording a woman’s body temperature throughout her menstrual cycle. A woman’s basal (resting) temperature rises just before ovulation. The rise in temperature tells a woman when she is most fertile.
   2. Billings method: Mucus is discharged from the cervix throughout a woman’s menstrual cycle. It changes from white and sticky to clear and stretchy (like an egg white) a day or two before ovulation. The billings method is a form of natural birth control that teaches a woman to recognize when she is fertile by examining her cervical mucus. To prevent pregnancy, a woman should refrain from sex during the time when she is most fertile.
   3. Sympto-thermal method: Combination of the basal body temperature method and the billings method to prevent pregnancy.
2. Spermicides: Substances that Kill Sperm

A spermicide is a chemical product that comes in the form of a foam, jelly, or cream. The purpose of a spermicide is to kill any sperm before it reaches the cervix. In order to increase the effectiveness of them, spermicides should be used with other barrier forms of birth control (condoms, diaphragms, cervical cap, etc.).

1. Barrier methods: Preventing Sperm from Meeting Egg
   1. Male condoms: Thin sheaths made from lamb intestine, latex rubber, synthetic or polyurethane elastomers that fit over the penis and trap sperm. Condoms are highly effective in preventing the transmission of STIs.
   2. Female condoms: Thin sheath or pouch that a woman wears during sex. It lines the vagina entirely and helps prevent STIs as well.
   3. Diaphragm: A shallow, dome-shaped, silicone cup inserted into the vagina to prevent pregnancy.
   4. Cervical cap: A cervical cap resembles a small thimble and is inserted into the vagina to prevent pregnancy
   5. Lea’s shield: Similar to the cervical cap this method is cup-shaped and made of silicone. It has a 1-way valve that allows the passage of cervical secretions.
   6. Contraceptive sponge: A soft, disk-shaped device that is made of polyurethane foam that covers the cervix.
2. Intrauterine devices (IUD)

An IUD is a small t-shaped piece of plastic or metal that is placed in the uterus to prevent fertilization. There are 2 types: one is covered with copper, and the other releases the hormone progesterone. IUDs have not been extremely popular in the United States. In the past, IUDs had a thread hanging outside of a woman’s body which easily spread bacteria causing pelvic inflammatory disease. Now, IUDs are very safe. They have polyethylene strings which are not as likely to cause infection.

1. Hormonal methods
   1. Oral contraception: Medications taken by women to prevent pregnancy. These pills may contain a combination of the hormones estrogen, progestin, or progestin alone. Combinations of estrogen and progestin prevent pregnancy by inhibiting the release of luteinizing hormone (LH) and follicle stimulating hormone (FSH). Pills are taken for 21 days followed by a 7 day break when a woman menstruates. The pill is highly effective if taken every day at the same time.
   2. Injectable contraception: A hormonal method for those who cannot remember to take the pill every day at the same time. Depo-Provera is an injectable medicine that prevents pregnancy for up to 3 months with each injection. It contains progestin and works by preventing ovulation by inhibiting the release of LH and FSH.

Sexual attraction

Sexual attraction is an important aspect of the sexuality of the person being observed, as well as of the person observing. Each person determines the qualities that they find attractive, which vary from person to person. A person's sexual orientation has a significant influence on which qualities they will find attractive. The qualities that people can find sexually attractive may depend on the physical quality, including both looks and movements of a person but can also be influenced by voice or smell as well as by individual preferences resulting from a variety of genetic, psychological, and cultural factors.

Creating a relationship

The Flirt, by Eugene de Blaas

People both consciously and subconsciously seek to attract others with whom they can form deeper relationships. This may be for companionship, for procreation, for an intimate relationship, besides other possible purposes. This involves interactive processes whereby people find and attract potential partners, and maintain a relationship. These processes, which involve attracting one or more partners, and maintaining sexual interest, can include:

• Flirting can be used to attract the sexual attention of another in order to encourage romance or sexual relations, and can involve body language, conversation, joking or brief physical contact.
• Seduction is the process whereby one person deliberately entices another to engage in some sort of human sexual behavior. The medium of communication of sexual interest can be verbal or visual.
• Dating is the process of arranging meetings or outings with a potential partner to investigate or enhance their suitability for an intimate partnership.
• The prospect of physical intimacy is, at times, the most effective means of sexual attraction. This can be by way of an expression of feelings such as close friendship or love, including holding hands, hugging, kissing, or caressing.

Legal issues

Main articles: Human sexual activity § Legal issues, and Sex and the law

There are many laws and social customs which prohibit, or in some way have an impact on sexual activities. These laws and customs vary from country to country, and have varied over time. They cover, for example, a prohibition to non-consensual sex, to sex outside of marriage, to sexual activity in public, besides many others. Many of these restrictions are non-controversial, but some have been the subject of public debate.

Most societies consider it a serious crime to force someone to engage in sexual acts or to engage in sexual activity with someone who does not consent. This is called sexual assault, and if sexual penetration occurs it is called rape, the most serious kind of sexual assault. The details of this distinction may vary among different legal jurisdictions. Also, what constitutes effective consent in sexual matters varies from culture to culture and is frequently debated. Laws regulating the minimum age at which a person can consent to have sex (age of consent) are frequently the subject of debate, as is adolescent sexual behavior in general.

See also

• Index of human sexuality articles
• Mental roots of sexual orientation
• Outline of human sexuality
• Sex magic
• Sexologies: European Journal of Sexual Health (Revue Européenne de Santé Sexuelle)
• Sexology
• Sexualization
• Sociosexual orientation

Further reading

• Durham, Meenakshi G. (2012). TechnoSex: technologies of the body, mediated corporealities, and the quest for the sexual self. Ann Arbor: University of Michigan Press.

External links

• American Sexuality Magazine
• "Examining the Relationship Between Media Use and Aggression, Sexuality, and Body Image," Journal of Applied Research on Children: Informing Policy for Children at Risk: Vol. 4: Iss. 1, Article 3.
• Glossario di sessuologia clinica – Glossary of clinical sexology
• International Encyclopedia of Sexuality full text
• Janssen, D. F., Growing Up Sexually. Volume I. World Reference Atlas [full text]
• Masters, William H., Virginia E. Johnson, and Robert C. Kolodny. Crisis: Heterosexual Behavior in the Age of AIDS. First ed. New York: Grove Press, 1988. ix, 243 p. ISBN 0-8021-1049-5
• National Sexuality Resource Center
• Durex Global Sex Survey 2005 at data360.org
• POPLINE is a searchable database of the world's reproductive health literature.
• The Continuum Complete International Encyclopedia of Sexuality at the Kinsey Institute
• The Sexuality and Rights Institute
• The South and Southeast Asia Resource Centre on Sexuality
• MRI Video of Human Copulation
• "Naked Science: What's Sexy?". Naked Science. Episode 1. 13 February 2006. National Geographic Channel. {{cite episode}}: Unknown parameter |serieslink= ignored (|series-link= suggested) (help); Unknown parameter |seriesno= ignored (|series-number= suggested) (help)
• Young, Wayland. Eros Denied: Sex in Western Society. First paperback ed. New York: Grove Press, 1966, cop. 1964. 370 p.