I'm sorry to hear that this forum is closing down. Somehow this forum is unique. There are other places, where pedophiles exchange opinions, but this is the place where the more sober, scientific oriented people exchange ideas.
My explanation of paraphilias in general is based on the role instincts are playing or are supposed to play. Typically for humans is that instincts are not strong and are not dominating the behavior. Sometimes they interfere with normal behavior like in the fear of flying. At other times they are necessary, but get prevented by environment. Since boys behave irrational during puberty, albeit in a consistent way - i assume that this is very much an innate behavior like the fear of flying. Moreover, going in this manner seems to be necessary for the psycho-sexual development. If one stuns the weak impulses further, then one might not end up liking women at all. Too many obstacles are put in the way of boys in puberty. Somehow, this backfires. Not only do i think of the sexual repressive society, but also the influence overprotective mothers have on their sons. It is known that many homosexuals have a weak father and a dominant mother, also there is a more older brothers hypothesis. There could be more to it than just a few antibodies. Younger brothers observe all the obstacles with chasing girls and might not be enticed to do the same.
Evolution has made human instincts weaker and weaker up to the point where they become too weak. All papers i have read so far about it, seem to confirm this.