Gynecomastia is a swelling of the breast tissue in boys or men, caused by an imbalance of hormones estrogen and testosterone. Gynecomastia can affect one or both breasts, sometimes unevenly. Neonates, adolescent boys, and older men may develop gynecomastia as a result of normal changes in hormone levels, although there are other causes as well.
In general, gynecomastia is not a serious problem, but it can be difficult to cope with the disease. Men and boys with gynecomastia sometimes have chest pain and may feel embarrassed.
Gynecomastia can disappear on its own.