I read the book Luna, by Julie Anne Peters. I LOVED it. It was so good and you should definitely try reading it. Luna is about a girl and her brother. Regan's, brother, Liam is transgender or transexxual, meaning that he was born as a boy but on the inside he feels like he was meant to be a girl. He hides it all his life, and only "dresses" (dresses up like a girl) at night, until finally he feels he can't hide who he is anymore. He decides to come out at possibly the least opportune moment for Regan because a boy in her chemistry class has finally taken interest in her, but she feels like when he finds out about Luna (Liam) that he'll freak out.
I know that a lot of people who read this post won't want to go anywhere near that book. I personally thought that it would make me uncomfortable, but the sincere and natural way that Peters wrote her book made it all seem natural. I really hope you take the time to read this!