I'm not sure if you know this, but Equestria Daily posts huge amounts of fandom material with no sexual content at all, while FIMFiction has a filter for mature content that's set by default. So if you want to browse pony stuff with your young children, you can do so safely on either of the two largest repositories on the Internet. Since fanfiction is so famously terrible in any fandom, you'll probably have a more fruitful time reading by yourself and then sharing your favorites. Take care
I appreciate this a lot, and I know that these archives exist. And as a point of clarification: my young child arrives sometime in late April/early May, and I doubt he'll be born clamoring for a lot of MLP fanworks (though if he is, I may have to call Ripley's Believe It or Not!).
That said, while I really do appreciate being given this resource, it's not something a lot of parents necessarily have if they're going to go on a search for MLP fanworks, and without the efforts of things like Safe Search Wrap Up (which I alluded to here), they're going to come across a LOT that they don't want to see and even more, that they don't want their kids to see.
I'm not saying that people shouldn't write what they enjoy or draw what they enjoy. I am saying that it's irresponsible to not put that stuff where kids can't find it--and really, that applies to all fandoms, but we're talking about bronies in specific here.