It is normal for a 12-year-old boy to grow a beard, but it is not normal for a 12-year-old girl to grow a beard. 12 years old is at puberty, in the human growth and development of the more vigorous period, the male into puberty androgen secretion is more exuberant, the body began to undergo some changes, such as growing a beard, pubic hair, armpit hair, the voice began to become thicker, the reproductive organs gradually tend to mature development, etc., so the male 12 years old long beard is normal. If the female, in the female 12-year-old beard may be due to the higher level of androgen, estrogen level is lower due to this phenomenon is not normal. If the child appears to be 12 years old beard and beard is very lush, should seek medical attention to clarify the cause, and timely intervention, so as not to affect the child’s physical and mental development.