Really good story! Very good idea :) I love that
I've always loved this concept. A change that isn't noticed by someone. I also like the idea of it being the other way around: He still has a male body but everyone treats him like a girl; and another that he thinks he's always been a girl, but he's treated like the male he truly is; and of course he knows he's been put in the body of a woman, but still has his identity, so now he has to perform tasks (Like Sports) as he used to do, but now he's not strong enough, has to still take of his female body which is makes it even harder.