Jack Ferraiolo, who wrote Sidekicks, has written a blog post about the response to the "erection scene" in that book. He raises the question of whether male sexuality is less accepted in novels for young people than the more common female puberty talk.
I liked the book. I found the scene in question both funny (for me) and humiliating (for the character). Jack wanted to be careful not to get into "gender politics," so I'll do it. Why is it okay for girls to read about characters dealing with sexual issues that they face, and thus have the opportunity to "try out" responses to, but it's not okay for boys? Not that any boy reader is ever going to have to worry about "trying out" a response to being caught with an erection in public while wearing a Spandex superhero costume. But you'd think the lack of reality in the situation would make it more acceptable. What's the problem here? Could it be that there something about male sexuality that is aggressive and scary whereas female sexuality is passive and nonthreatening?
Oh, I really am getting into gender politics.
Quite apart from the whole gender thing, Jack's blog post is interesting because it gives some insight into how long an author might dwell on a situation or idea--and build upon it--before beginning to write.