I think... games with Mpreg themes should have a warning in the title like "(Mpreg)" to let people know, so those who don't like that genre won't accidentally click on it. I'm just saying this because I'm someone who doesn't like Mpreg either, but I'm not hating on it or anything—I just want there to be a clear indication, like This is an Mpreg game or This is an Fpreg game. But yeah, that's just the opinion of an ordinary person.
Proper tagging will be required for all jam submissions - that alone should help a good bit.
We will also ask for people to give their games that little... I forgot the name, but the brief description that Itch displays below the thumbnail, so we could also ask people to write that it's mpreg in there?