I dunno about this, for me anyway. If I see a pretty girl who is around 13 or so, I can see she is pretty, and I'll say to myself "she's going to be beautiful when she grows up" or what have you, but the underdevelopment of the rest of her body will just totally block any kind of sexual attraction from forming in my mind.
I agree with there being no moral wrongdoing with simply being attracted though, and not acting out on it. I kind of wonder how often that occurs though. How many people who are attracted primarily to young people (illegal), actually fight through the urge their entire lives without slipping up?
On that last point, another Louis Theroux docu is pretty interesting. It's about a mental institution (for the lack of a better term) where convicted pedo's who are deemed hopeless are put through a process where it is hoped they are cured of their urges. Here it is anyway for those interested: http://www.youtube.com/watch?v=IEt3-kuVl5Y
Can you imagine how awful life would be with that kink?