Ill try to find what I know of. I read a study a very, very long time ago (like in a magazine long ago) that I think they said that there is a mechanism in your brain that pushes you to be attracted to someone closer to your age rather than not and in pedos that piece is broken.
However, There is a LOT of evidence out there that kids that get abused end up becoming abusers too so there is that to take into account.
Being attracted to someone relatively younger has an easily observed reproductive advantage - 25 year olds are more likely to succesfully bear healthy offspring than 35 year olds. Much the way that washing your hands has an advantage because you're more likely to live longer and have more children. That obviously goes off the rails if taken to an extreme. If you wash your hands 45 times a day you'll scrub your skin off and get an infection. If you molest 9 year olds you'll get capped by your neighbors or declared the "prophet" of a pedo religion.
Sexual behavior is also massively a learned behavior. If your mom married a drunk, you're likely to immitate that behavior. If you got bad-touched by a pedo, you're also highly likely to immitate that behavior either directly (pedos reproduce by molesting kids), or indirectly through homosexuality. Homosexuality is largely driven by pedos. E.g. lesbians were molested as children at 23x the baseline rate.
I see, i must have seen something about it in passing and it stuck.
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