There are many people who are undergoing sexual reconstructive surgeries these days and get there sex changed. I had a case where a girl wanted to become a boy after the surgery but as she was still not old enough for surgery the family approached me for treatment. We treated her on the lines of OCD and today she is happy living like a girl even after an year.
What a disaster it would have been if she underwent surgery looking at greater prevalence of psychiatric problems in such people after surgery.