Pubic hair on the vulva is one of the secondary sex characteristics of women, and pubic hair has certain functions, on the one hand, it can cause strong sexual desire and increase sexual pleasure, on the other hand, it also has a protective effect on the vagina and vulva. However, some women who have entered puberty or sexual maturity do not have pubic hair, which is mainly due to the following reasons: 1) congenital developmental abnormalities of the reproductive system, no ovaries, which can not secrete normal sex hormones leading to the absence of pubic hair, accompanied by the absence of menstruation, breasts do not develop; 2) although the ovaries have ovarian dysfunction, which can not secrete sex hormones normally, will lead to the absence of pubic hair, menstruation and breasts do not develop; 3) the absence of pubic hair, menstruation, and breasts do not develop. Although there are ovaries, the ovaries do not function properly and cannot secrete sex hormones normally, which will also lead to no pubic hair growth, no menstruation and no breast development; 3. The reason why some women have too little pubic hair or no pubic hair at all may be related to hereditary factors.