Gynecomastia is also known as "man boobs" & "gyno", occurs when a feminine contoured breast develops in a man.  It affects up to 20% of adolescent males. All humans are born with hormonally sensitive mammary tissue. During puberty, a rise in estrogen naturally occurs in women. This stimulates the mammary tissue to develop into a breast form associated with feminity. During a woman's life, many factors (pregnancy, age, disease) will affect the breast size, shape, symmetry, nipple, and areolar dimensions.  Similarly, mammary tissue in males will also undergo changes during puberty. In general, estrogen levels are lower in males and breast development usually does not exceed beyond the pigmented skin of the areola surrounding the nipple. For unknown reasons, some men have continued growth of their mammary tissue into feminine-shaped breasts. If you are a man, the progressive development of a feminine breast is one of the most common and distressing life events. Usually, there is no identifiable cause. This is medically known as developmental gynecomastia. Special medical investigations are not necessary with this type of gynecomastia. Breast development in preadolescent children is abnormal and should be medically investigated. Diseases of the pituitary gland or testes may cause prepubescent breast development. Similarly, adult men who develop gynecomastia should be evaluated for recreational drug use (marijuana), medications, illness, or endocrine dysfunction. When one breast enlarges in an adult man, an urgent and thorough evaluation to rule out male breast cancer is warranted.  Fortunately, developmental gynecomastia is well managed with male breast reduction. Dr. Chen Lee understands that gynecomastia surgery requires attention to detail. To yield the best possible cosmetic outcome, he will formulate a surgical plan based on your unique breast anatomy.