Sexual characteristics

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Sexual characteristics are physical traits of an organism (typically of a sexually dimorphic organism) which are indicative of its biological sex. These can include sex organs used for reproduction and secondary sex characteristics which distinguish the sexes of a species, but which are not directly part of the reproductive system.

Humans[edit]

In humans, sex organs or primary sexual characteristics, which are those a person is born with, can be distinguished from secondary sex characteristics, which develop later in life, usually during puberty. The development of both is controlled by sex hormones produced by the body after the initial fetal stage where the presence or absence of the Y-chromosome and/or the SRY gene determine development.

Hormones that express sexual differentiation in humans include:

Typical sexual characteristics[edit]

The following table lists the typical sexual characteristics in humans:

Level of definition Female Male
Biological levels (Sex)
Sex chromosomes XX in humans XY in humans
Primary sexual characteristics
Gonads ovaries testes
Level of sex hormones oestrogen, gestagen androgen, testosterone
Anatomy of internal genitalia clitoral crura, vagina, uterus, fallopian tubes corpora cavernosa, prostate, vas deferens, seminal vesicles
Anatomy of
external genitalia
glans clitoridis, labia, vulva, clitoral hood
perineal urethra
glans penis, scrotum, phallus, foreskin
fused perineum
Secondary sexual characteristics
females have larger breasts, menstrual cycle, wider hips, shorter height, more body fat, 10 to 12% less lung capacity,[1] smaller heart[2] Facial and body hair, smaller breasts, lower drop in vocal pitch frequency, development of "triangular" body form, higher height, less body fat, narrower hips, more lung capacity
Both sexes Pubic hair, underarm hair

Invertebrates and plants[edit]

In invertebrates and plants, hermaphrodites (which have both male and female reproductive organs either at the same time or during their life cycle) are common, and in many cases, the norm.

In other varieties of multicellular life (e.g. the fungi division, Basidiomycota) sexual characteristics can be much more complex, and may involve many more than two sexes. For details on the sexual characteristics of fungi, see: Hypha and Plasmogamy.

See also[edit]

References[edit]

  1. ^ Bellemare F, Jeanneret A, Couture J (2003). "Sex differences in thoracic dimensions and configuration". Am J Respir Crit Care Med. 168 (3): 305–12. doi:10.1164/rccm.200208-876OC. PMID 12773331.
  2. ^ Glucksman A (1981). Sexual Dimorphism in Human and Mammalian Biology and Pathology. Academic Press. pp. 66–75.