A.G.
My son is 9 and has The Boy's Body Book. He likes it, and uses it as a reference book. I read it before I gave it to him, and thought it was pretty good. We talk a ton, too, of course, but my son finds it comforting to have a book to go to when he doesn't feel like talking. Here is a link on amazon:
http://www.amazon.com/Boys-Body-Book-Everything-Growing/d...