If anything it undermined the most likable things about him.
Depends on your POV, but to me this reveal made him more
likable. He's not perfect after all. He's been forced to hide this secret his entire life or risk losing everything. He already had a strained relationship with his parents because of it. Our whiz kid doctor was severely flawed as a child, and his dad had him "fixed." Now he has to face this dark secret again. Now he has to tell his friends. Now he must live with the stigma. Suddenly there's a reason to have sympathy for the guy. And parents pushing too hard in one way or another -- now many of us can actually relate to him too. It was a beautiful episode that added much-needed depth to this character. And it also added a layer of humor to his relationship with O'Brien. IMO.