Unwanted hair growth can happen in both males and females. In women, this hair growth, called hirsutism, occurs where hair does not often appear, such as the chin, chest or back. Puberty, pregnancy, menopause, and aging can cause increased hair growth in areas that have not been affected before. Unwanted hair growth affects 5-15% of all women, and many estimates show that to some extent, 40% of women have unwanted facial hair. While women are affected more often, men may also be affected. A study in 2009 found that in the United States, 84% of men engage in more hair removal treatments, and hair removal clients in the United Kingdom have significantly increased. This unwanted hair growth can be caused by an increase in androgen hormone levels and is associated with a number of endocrine disorders, whether they are adrenal or ovarian disorders, diabetes, or thyroid problems. Hair growth may also be due to causes like heredity, medication side effects, or stress.