12-year-old beard is usually a normal phenomenon after the boys enter puberty, usually does not significantly affect the height. Girls 12 years old long beard may be the abnormal secretion of hormones caused by the disease, may affect the height, it is recommended to consult a doctor in time. The age of puberty is not only affected by racial and environmental factors, but also varies greatly between genders and individuals. In most cases, it is normal for boys to enter puberty at the age of 12, when secondary sexual characteristics begin to develop, which in boys mainly includes beard growth, voice coarsening, testicular enlargement and spermatorrhea, etc. If a girl grows a beard, it may be due to hormonal abnormalities. If a girl grows a beard it may be caused by a disease with abnormal hormone secretion. Puberty is also the peak of adolescent growth and development, at this time should be supplemented with adequate nutrition, affecting the development of height due to genetics, nutrition, exercise, sleep, as well as hypothyroidism and other diseases. For boys, growing a beard is not a factor that affects height development, so a 12 year old with a long beard usually does not affect height. 12 year olds with long beards who have abnormal height development can go to the hospital and ask the doctor to make a judgment.