What are secondary sexual characteristics?

Secondary sexual characteristics, also known as "secondary sexual characteristics". A physiological characteristic that appears during adolescence and is retained mostly or entirely in adulthood. In men, the symptoms include significant growth of pubic hair, armpit hair, and beard, development of muscles, thick bones, protruding larynx, and deepening of voice.

In women, breasts bulge, pubic and armpit hair grow, pelvic width increases, and plump fat appears under the skin. Although these physiological characteristics of men and women are genetically determined, their final appearance and maturity depend on the promotion of gonadal endocrine. Otherwise, secondary sexual characteristics may never appear.

The age at which secondary sexual characteristics appear differs in different countries and regions, in different historical periods of the same country, and between men and women. The more consistent conclusion is that boys develop secondary sexual characteristics two years later than girls.

Extended information:

1. The origin of the concept of secondary sex characteristics:

Secondary sex characteristics, also known as "secondary sex characteristics", this concept is It was first proposed by John Hunter in the 18th century. He used the term to refer to the comb and other sexual characteristics of a rooster, but there is no precise definition.

In the 19th century, Darwin (1809~1882), a British biologist and founder of the theory of evolution, described extensively the manifestations of secondary sexual characteristics in his famous book "Human Evolution and Sexual Selection", but There is no precise definition of this concept.

At the end of the 19th century and the beginning of the 20th century, the famous British scholar Sir Ellis defined secondary sexual characteristics as follows in his monograph "Men and Women: A Study of Human Secondary Sexual Characteristics": Secondary sexual characteristics are highly differentiated and different characteristics of the sexes that enhance mutual attraction between the sexes and thereby promote the union of sperm and egg. Of course, secondary sexual characteristics are not only formed for sexual attraction, but also have many practical uses.

The evolution of organisms from asexual to sexual can at least show that sexual differentiation plays a positive role in the evolution of species, which has more advantages than disadvantages. In addition to humans, who have obvious differences in secondary sexual characteristics between the sexes, many animals also have secondary sexual characteristics, and they have many striking similarities with humans.

For example: a male lion's sideburns, a male peacock's tail feathers, a stag's antlers, etc. correspond to the thick body hair on a male body. Although there is no colorful hair or large aggressive horns, it is still Like most male animals, it has a stronger, larger and more powerful body.

Women, like female animals, have less body hair and are more slender and compact. However, from a human aesthetic perspective, it is difficult for most people to compare it with human sexual characteristics, but it can actually be understood.

2. Classification of sexual characteristics

The primary sexual characteristics refer to the reproductive organs. From the fifth week of embryonic development, it gradually differentiates into primary sexual characteristics, which are already present when the baby is born, and are used to distinguish male or female.

Secondary sex characteristics refer to a series of gender-related characteristics that begin to appear in both sexes during puberty, also known as secondary sex characteristics. For example: men grow beards, pubic and armpit hairs appear, protruding Adam's apple, thick bones, well-developed muscles, deep voices, etc. Women's breasts enlarge, pubic and armpit hairs appear, the pelvis is wide, the fat on the chest, shoulders, buttocks and hips increases, and the voice is high, etc. .

Tertiary sexual characteristics refer to the psychological, behavioral, habits, interests, physical and other characteristics after entering puberty. ?

Baidu Encyclopedia - Secondary Sexual Characteristics

Baidu Encyclopedia - Sexual Characteristics