Girls should not usually grow a beard. If a girl grows a beard, most cases are pathological, so the first thing to look for is the cause of the beard. Most of them are due to excessive androgens in the body, so they show some manifestations of masculinity and may appear to grow a beard. The causes of beard growth in women include the following: 1. There are problems with the ovaries, for example, some patients with polycystic ovary syndrome are prone to beard growth. There are also tumors on the ovaries, which may produce androgenic hormone excess, also will grow beard; 2, there are some other diseases, such as adrenal gland diseases, there will be patients with hirsutism, that is, the performance of long beard; 3, there is no pathological factors, but some idiopathic hirsutism, may also grow beard, which may have a certain relationship with the family, or with this type of people are more sensitive to androgens. The reason for this is that it is not a problem.