Promiscuity, in human sexual behaviour, is the practice of having casual sex frequently with different partners or of being indiscriminate in the choice of sexual partners. The term can carry a moral judgement and is viewed in the context of a mainstream social ideal for sexual activity to occur within exclusive committed relationships. A common example of behavior viewed as promiscuous within the mainstream social ideals of many cultures is a one-night stand.
What sexual behavior is considered promiscuous varies between cultures as does the prevalence of promiscuity, with different standards often being applied to different genders and civil status. Feminists have traditionally argued that there is a significant double standard between how men and women are judged for promiscuity. Historically, stereotypes of the promiscuous woman have tended to be negative, such as "the slut", while male stereotypes have been more varied, some expressing approval, such as "the stud" or "the player", while others imply societal deviance, such as "a womanizer". A scientific study published in 2005 found that promiscuous men and women are judged equally harshly and a recent poll showed that both genders tend to express strong preference for sexually conservative partners.
Promiscuity is common in many animal species. Some species have promiscuous mating systems, ranging from polyandry and polygyny to mating systems with no stable relationships where mating between two individuals is a one-time event. Many species form stable pair bonds but still mate with other individuals outside the pair. In biology, incidents of promiscuity in species that form pair bonds are usually called extra-pair copulations.
Accurately assessing people's sexual behavior is difficult, since there are strong social and personal motivations, depending on social sanctions and taboos, for either minimizing or exaggerating reported sexual activity.
American experiments in 1978 and 1982 found that the great majority of men were willing to have sex with women they did not know, of average attractiveness, who propositioned them. No woman, by contrast, agreed to such propositions from men of average attractiveness. While men were in general comfortable with the requests, regardless of their willingness ("Why do we have to wait until tonight?", "[I'm sorry], I'm married"), women responded with shock and disgust ("You've got to be kidding", "What is wrong with you? Leave me alone").
The number of sexual partners an individual has had in their lifetime varies widely within a population. A 2007 nationwide survey in the United States found that the median number of female sexual partners reported by men was seven and the median number of male partners reported by women was four. It is possible that men exaggerated their reported number of partners, women reported a number lower than the actual number, or a minority of women had a sufficiently larger number than most other women to create a mean significantly higher than the median, or all of the above (see Pareto principle). Twenty-nine percent of men and nine percent of women reported to have had more than 15 sexual partners in their lifetimes. Studies of the spread of STIs consistently demonstrate that a small percentage of the studied population have more partners than the average man or woman, and a smaller number of people have fewer than the statistical average. An important question in the epidemiology of sexually transmitted infections is whether or not these groups copulate mostly at random (with sexual partners from throughout a population) or within their social groups (assortative mixing).
A 2006 comprehensive global study (analyzing data from 59 countries worldwide) found no firm link between promiscuity and STIs, with poverty and mobility being more important factors. This contradicts other studies. In 2004, "HIV infection rates had fallen from 15% to 5% in Uganda over the past decade. The experts said a nationwide campaign encouraging people to stick with regular partners contributed to the fall."
In 2008, a U.S. university study of international promiscuity found that Finns have had the largest number of sex partners in the industrialized world, British people having the largest number among big western industrial nations. The study measured one-night stands, attitudes to casual sex, and number of sexual partners.
Researchers said Britain's position on the international index "may be linked to increasing social acceptance of promiscuity among women as well as men". Britain’s ranking was "ascribed to factors such as the decline of religious scruples about extramarital sex, the growth of equal pay and equal rights for women and a highly sexualised popular culture".
The top-10 ranking OECD nations with a population over 10 million on the study's promiscuity index, in descending order, were the United Kingdom, Germany, the Netherlands, the Czech Republic, Australia, the United States, France, Turkey, Mexico, and Canada.
A non-scientific survey conducted in 2007 by condom-maker Durex measured promiscuity by a total number of sexual partners. The survey found that Austrian men had the highest number of sex partners of males globally with 29.3 sexual partners on average. New Zealand women had the highest number of sex partners for females in the world with an average of 20.4 sexual partners. In all of the countries surveyed, except New Zealand, men reported more sexual partners than women.
One study found that people from developed Western countries had more sex partners than people from developing countries in general, while the rate of STIs was higher in developing countries.
According to the 2005 Global Sex Survey by Durex people have had on average 9 sexual partners, the most in Turkey (14.5) and Australia (13.3), and the least in India (3) and China (3.1).
A 1994 study in the United States, which looked at the number of sexual partners in a lifetime, found that 20% of heterosexual men had only one partner, 55% had two to twenty partners, and 25% had more than twenty partners. More recent studies have reported similar numbers.  Early studies found men with homosexual contact were more likely to have a very large number of sexual partners. A 1989 study found a very high number of partners (over 100) to be present though rare among gay men. The difference was attributed to sampling problems with earlier studies, and the influence of AIDS.
The words womanizer/womaniser, playboy, stud, player, ladies' man, lady killer, roué, and rake may be used in reference to a man who has romantic affairs or sexual relations, or both, with women and will not marry or commit to a relationship. The names of real and fictional seducers have become eponymous for such promiscuous men. The most famous are Lord Byron, John F. Kennedy, Wilt Chamberlain, Howard Hughes, the historical Giacomo Casanova (1725–98), the fictional Don Juan, who first appeared in the 17th century, the fictional Vicomte de Valmont from Choderlos de Laclos's 18th-century novel Les Liaisons Dangereuses (Dangerous Liaisons), and Lothario from Nicholas Rowe's 1703 play The Fair Penitent. James Bond, Chuck Bass, James T. Kirk, Tony Stark, Bruce Wayne, Charlie Harper, Sam Malone, Joey Tribbiani and Barney Stinson are fictional characters that can be considered womanizers.
During the English Restoration period (1660–88), the term rake was used glamorously: the Restoration rake is a carefree, witty, sexually irresistible aristocrat typified by Charles II's courtiers, the Earl of Rochester and the Earl of Dorset, who combined riotous living with intellectual pursuits and patronage of the arts. The Restoration rake is celebrated in the Restoration comedy of the 1660s and the 1670s. After the reign of Charles II, and especially after the Glorious Revolution of 1688, the rake was perceived negatively and became the butt of moralistic tales in which his typical fate was debtor's prison, permanent venereal disease, and, in the case of William Hogarth's A Rake's Progress, syphilis-induced insanity and internment in Bedlam.
In 1994, a study in the United States found that almost all married heterosexual women reported having sexual contact only with their husbands, and unmarried women almost always reported having no more than one sexual partner in the past three months. Lesbians who had a long-term partner reported having fewer outside partners than heterosexual women. More recent research, however, contradicts the assertion that heterosexual women are largely monogamous. A 2002 study estimated that 45% to 55% of married heterosexual women engage in sexual relationships outside of their marriage. While the estimates for heterosexual males in the same study were greater (50%–60%), the data indicates that a significant portion of married heterosexual women have or have had sexual partners other than their spouse as well.
Since at least 1450, the word slut has been used, often pejoratively, to describe a sexually promiscuous woman. In and before the Elizabethan and Jacobean eras, terms like "strumpet" and "whore" were used to describe women deemed promiscuous, as seen for example in John Webster's 1612 play The White Devil. In some tribes of Sierra Leone, "A woman who is a Paramount Chief may have sexual intercourse with as many men as she pleases."
Evolutionary psychologists propose that a conditional human tendency for promiscuity is inherited from hunter-gatherer ancestors. Promiscuity increases the likelihood of having children, and thus evolutionary fitness. Female promiscuity is advantageous in that it allows females to choose fathers for their children who have better genes than their mate, to ensure better care for their offspring, have more children, and as a form of fertility insurance. Male promiscuity was likely advantageous because it allowed males to father more children.
Primitive promiscuity (or original promiscuity) was the (largely discredited) 19th-century hypothesis that humans originally lived in a state of promiscuity or "hetaerism" prior to the advent of society as we understand it.
Extra-pair copulation in non-humans
In the animal world, some species, including birds such as swans and fish such as Neolamprologus pulcher, once believed monogamous, are now known to engage in extra-pair copulations. Although social monogamy occurs in about 90 percent of avian species and about 3 percent of mammalian species, investigators estimate that 90 percent of socially monogamous species exhibit individual promiscuity in the form of extra-pair copulations.
- Female promiscuity
- Mating system
- Sexual addiction
- Sociosexual orientation
- Sperm competition
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