In my opinion, shoving a filter on a computer and thinking your job is done as a parent is one of the most irresponsible things you can do. I'm sure I'll get lots of QFTs if I just left it at that, so I'll post something I know you'll disagree with. There's is a pretty good case for censorship to a degree, and if you want to slap a filter on the web while your child is you go ahead. But don't forget your own childhood. Don't try and tell me you didn't know about love until your parents sat you down and told you about the birds and the bees. You probably looked up certain naughty words in the dictionairy with a couple of friends and started giggling about them. You probably said one at the dinner table once and got your mouth washed out with soap. Even if you didn't, you probably knew someone who did and picked it up from them. You can't monitor every vector as a parent, and you shouldn't try to. Instead, take a close look at the failings of abstinance only love education. It didn't stop kids from having love, it just made them do it unsafely.
As hard as it is, you'll have to admit to yourself that you aren't going to be able to stop someone from looking at research once they've started. They'll look for every possible way around.
Instead, tell them to be careful what they download, because they'll infect the computer with nasty trojans, and then you'll have to kick they're ass. Warn them that if it starts to get in the way of visiting grandma/doing charity work/saving the world, you'll have to moderate their time. And if they're interested in any sort of career in politics, they'd better stop now.