Check out a book called "It's Perfectly Normal". I haven't read it myself (too late to help me
), but the opinions I've read about it are pretty encouraging. Liberal minded groups praise it for its honesty and its frank discussions and depictions of puberty and human sexuality, and ultra conservative groups consider it pornographic.
If you do buy the book, make sure you read it wit great interest in front of your son. When he asks what you're reading, tell him "it's a book on how you're going to change in the next few years",
but don't let him read it just yet! Tell him you're not done with it, and that he can read it once you're finished.
From time to time, look inside the book, look at your son, giggle, and say "cool!" Then put down the book. Do this before he hits puberty, otherwise his mood will do a total 180 and he won't react the same way. Corner him while he's still a kid!
No, I don't have any kids, and I don't know if this will work. But I believe if my parents were more honest and less ashamed about sex when I was a kid, it would have avoided my problems with a lot of awkward teenage situations which were truly "perfectly normal".