what Dante said, and further...

It has been suggested, also in the general scientific community, that the roots of paedophilic attraction might have to do something with a genetic disposition towards attraction to neotenic features.

While other research has discovered that the features of a platonic-ideal Most Attractive Female, designed through average of everyone-in-the-sample's preferences roughly match those of an average 16yo, a strong preference for neoteny would suggest significantly higher attraction for the average features of younger stages.

Neoteny, in addition, does what many other theories don't: give an evolutionary reason for paedophilia to appear in the genetic pool and not select itself out. Afaik, only alloparenting and first-come-first-served do the same thing. Probably too, the truth is more complicated and all of these, along with other non-genetic and even non-biological factors intervene.

The salamander genus Ambystoma is very interesting as it contains species that have started doing rather unusual things, evolutionarily speaking. One of those things is the appearance of species that are wholly neotenic - ie, that are able to live their entire lives, including reproductive cycles, in larvae form, exceptionally among amphibians. Among other things, this implies that all individuals of such species are, technically, paedophilic. If, for some reason, paedophile humans were the only ones to ever breed, it would probably follow that in a couple thousand years the phenotypes of all humans would be a lot more child-looking than they are now.