Well, one of the enormous problems here is that there really isn’t very much evidence either way, and what little evidence there is is of dubious quality. Most studies are done on the basis of self-reporting, which is fine for things people are proud to talk about like politics, but with “are you a pedophile, what is that like for you” some people are somewhat prone to fibbing, would you believe? I’ll just ask, do you buy the purported “gateway drug” effect in any other context, and if so, to what extent do you think it’s valid in that context?