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Before puberty, the genital area of both boys and girls has very fine vellus hair, referred to as Tanner stage 1 hair. In response to rising levels of androgens as puberty begins, the skin of the genital area begins to produce thicker, often kinkier, hair with a faster growth rate. The onset of pubic hair development is termed pubarche. The change for each hair follicle is relatively abrupt, but the extent of skin which grows androgenic hair gradually increases over several years.
In most girls, pubic hair first appears along the edges of the labia majora (stage 2), and spreads forward to the mons (stage 3) over the next 2 years. By 3 years into puberty (roughly the time of menarche for most girls), the pubic triangle is densely filled. Within another 2 years pubic hair also grows from the near thighs in most young women, and sometimes a small amount up the line of the abdomen toward the umbilicus.
In boys, the first pubic hair appears as a few sparse hairs on the scrotum or at the upper base of the penis (stage 2). Within a year, hairs around the base of the penis are too numerous to count (stage 3), and within 3 to 4 years, hair fills the pubic area (stage 4), and by 5 years extends to the near thighs and upwards on the abdomen toward the umbilicus (stage 5).
Other areas of the skin are similarly, though slightly less, sensitive to androgens and androgenic hair typically appears somewhat later. In rough sequence of sensitivity to androgens and appearance of androgenic hair, are the armpits ( axillae), perianal area, upper lip, preauricular areas (sideburns), periareolar areas (nipples), middle of the chest, neck under the chin, remainder of chest and beard area, limbs and shoulders, back, and buttocks.
Although generally considered part of the process of puberty, pubarche is distinct and independent of the process of maturation of the gonads that leads to sexual maturation and fertility. Pubic hair can develop from adrenal androgens alone, and can develop even when the ovariesOvaries are a part of a female organism that produces eggs. Mammalian ovaries Ovaries are part of the vertebrate female reproductive system. Normally, a female will have two ovaries, each performing two major functions: producing eggs and secreting hormon or testes are defective and nonfunctional. See puberty for details.
There is little if any difference in the capacity of male and female bodies to grow hair in response to androgens. The obvious sex-dimorphicSexual dimorphism is the systematic difference in form between individuals of different sex in the same species. For example, in some species, including many mammals, the male is larger than the female. In others, such as some spiders, the female is large difference in hair distribution in men and women is primarily a result of differences in the levels of androgen reached as maturity occurs.
Patterns of pubic hair vary among people. On some people, pubic hair is thick and/or coarse, while on others it may be sparse and/or fine.
Pubic hair and axillaryArmpit hair is the composition of hair in the underarm area. This hair normally starts to appear between mid and late puberty, and many times even earlier. The physiological purpose of this hair is yet to be explained, but it has been suggested that it se (armpit) hair can vary in color considerably from the hair of the scalp. In most people it is darker, although it can also be lighter. On many men, pubic hair color is closest to the color of their beards (before their beards start turning white with age), which again can vary from the color of the hair on top of the head. On most women, the pubic patch is triangular and lies over the mons veneris, or mound of Venus. On many men, the pubic patch tapers upwards to a line of hair pointing towards the navel. As with axillary (armpit) hair, pubic hair is associated with a concentration of sebaceous glandThe sebaceous glands are glands found in the skin of mammals. They secrete an oily substance called sebum, that is made of fat and the debris of dead fat-producing cells. It acts to protect and waterproof hair and skin. Sebaceous glands can usually be fous in the area.
Like other hair, pubic hair may be infested by lice, with a specific category of pubic lice.
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