There is actually extremely little evidence for anything when comes to individuals, sexual content, and their sexual fantasies. There is even less evidence available for anything when it comes to minors.

I've read papers on the topic, and the good papers always point out that there is almost no focus on any potential positives. Many "authors" have already made up their minds before they've even started conducting research, and that's only if they manage to get funding (everything sex related gets very little or no research funding).