Sexual characteristics are physical traits of an organism (typically of a sexually dimorphic organism) which are indicative of or resultant from biological sexual factors. These include both primary sex characteristics, such as gonads, and secondary sex characteristics.
Humans
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.
Male primary sex characteristics are the penis, the scrotum and the ability to ejaculate when matured. Female primary sex characteristics are the vulva, vagina, uterus, uterine tubes, cervix, and the ability to give birth and menstruate when matured.
Hormones that express sexual differentiation in humans include:
- estrogens such as estradiol
- progestogens such as progesterone
- androgens such as testosterone
The following table lists the typical sexual characteristics in humans (even though some of these can also appear in other animals as well):
{| class="wikitable"
!Level of definition
!Female
!Male
|-
| colspan="3" | Primary sexual characteristics
|-
| Gonads
| Ovaries
| Testicles
|-
| Levels of sex hormones
| High estrogen and gestagens (including progesterone), with variation across the menstrual cycle; lower androgens (including testosterone)
| High androgens (including testosterone) smaller heart
| More facial hair, more body hair, taller height, more muscle mass, development of "triangular" body form, smaller breasts, narrower hips, lower drop in vocal pitch frequency, less body fat, more lung capacity,
See also
- Mammalian gestation
- Reproduction
- Sex and gender distinction
- Sexual differentiation