This is a subject which I really try to face with an unbiased point of view; but I find myself pretty much failing, I think. Simply because, emotionally, I never even want to accept such a thing is justified.
Alright so. Pedophilia equals rape, in the way that a child would never consent to it because it doesn't even know what it is; the body isn't ready for such things.
If there are really people who feel attracted to babies and children, then I do feel sorry for them. But I cannot rationalize how that can be natural, or justified by their genes or something. For me, it equals mental illness, although I have absolutely no scientific evidence for this!
I can only compare it to animals. I'm not saying they rape youngsters, but for instance, male lions kill their enemy's offspring so their mothers can focus on raising his babies instead. This is not rape, but it's a way of dominating and making sure a line of birth is safe.
I don't know if it can be a fetish? Ugh. Maybe the idea of a helpess child totally turns a pedophile on? I don't know. Even if they manage to fight these feelings off and not succumb to them, I just... can't... accept it. For obvious reasons >.<
But a sexual orientation - as its name suggests, means a certain attraction to a certain gender/sex. And since children/babies are not genders/sex, it cannot be one; unless we change the definition of 'sexual orientation' but... yeah, you get the idea.