I recently finished reading Middlesex by Jeffrey Eugenides. In it, a fourteen-year-old girl learns that she is, in fact, a boy. The book is a very wide-ranging story told by the adult Cal in which he talks a great deal about his very interesting ancestors but also of his childhood and early adolescence when he was Calliope. (A Greek family.)
As I was reading those sections of the book, I wondered if any YA novels deal with the same situation.