The team encounters a teenage boy who collapsed from severe pelvic pain after playing basketball. Tests reveal the boy has genetic mosaicism, or both male and female DNA, and the boy’s parents inform House and the team that the boy is unaware of his condition. They consciously chose a gender for him when he was born and raised him accordingly. However, when his condition worsens and his life is threatened, the parents wonder whether they made the right decision. Meanwhile, Cuddy and Wilson suspect something is wrong with House when he starts acting way too nice. When they discover the shocking answer, they must face the prospect that House may be changed forever and leave for a different hospital or retire altogether from medicine.