Mark, 20 years old, comes to see you because he is embarrassed about his breasts. He first noticed a little swelling at age 14 but had not felt he was any different from his classmates until the last few years when his breasts had increased in size (Figure). He was in the taller quarter of his class, played tennis for the school and was doing well academically. His pubic and body hair started growing at the same time his breasts increased in size. He thinks his penis has always been small but he does have erections and ejaculations, although he has never had sexual intercourse. He now avoids getting undressed in public and takes care to wear a tight singlet and a loose shirt to hide his breasts.