Just my own thoughts:
Reduce boys' exposure to sexualised content. And I don't mean just porn, but advertising, movies and tv, and maybe even just people around. None of which would be popular, especially saying the sexualising of women's clothing and fashion is problematic for society.
Also something that might prove problematic in other ways - I do wonder if delaying "normal" sexual experiences so that young people are mainly sexually inexperienced until quite late may impact this kind of thing - I think a lot of younger people are relying an awful lot on their imaginations, or pornography, or in the case of girls smutty books, to a really significant degree for years. And because there is no real person involved to remain interesting and compelling, and because it's unfocused, that tends to move toward some odd and abstract things.
I'm not really thinking that teens being promiscuous is the answer, but maybe more real dating, and getting away from the long extension of adolescence that has people marrying and having kids quite late.
It seems to me fetishes start weak, and can potentially be out-competed at an early stage by something better. They get stronger over time and the more they are indulged.
People recognising fetishes as something that will grow and are a problem from early on may also give some tools at that stage to repress them. But they will need to have some kind of practise at sexual self-control, and an awareness that not all fantasy is healthy, and not all sexual expression is harmless as long as there is consent.
All of these are things our society directly contradicts constantly, so I think we are now maximising the number of people developing these kinds of sexual fetishes. (Mainly men, but if you read over at the reddit/detrans you will see some young women describe experiencing something similar to AGP.)