How old is the boy to grow pubic hair and there is no absolute time standard, with each person’s personal constitution, physical condition, heredity and other factors related to the general situation in puberty at about 12 years old when the pubic hair began to grow. Men in the process of growth and development, with the secretion of androgen, the sex organs began to develop, the development of secondary sexual characteristics, there will be a long pubic hair, the general situation in the puberty of 12 years old when the pubic hair began to grow, and with the growth of age, the body function changes, the growth of pubic hair increased. Subject to personal constitution, external environment, genetic factors are different, into the age of puberty also exists a relatively large individual differences, how much long pubic hair and no absolute time standard, if the situation does not grow pubic hair, should go to the hospital in time for consultation and treatment.