Search Engines like google deal with this problem all the time. You can find any sort of thing in Google, but you can also search with 'safe search' turned on, which presumably helps a bit with that problem.
Our job is actually a lot easier than google's in this regard, because they might link to anything out of billions and billions of pages. We only have a few hundred thousand.
We could have a flag or marker for 'content advisory'. As with Google, it wouldn't actually stop anyone from clicking on anything. (I don't suppose curious children are much delayed if they want to see something on google that is filtered.)
I'm not 100% sure this makes sense, but it *is* a solution favored by a lot of mainstream websites, and it does have some acceptability on those grounds.
--Jimbo