I remember looking up "Reproduction" in my school library's Encyclopedia back in fourth grade, and seeing fairly graphic pictures and content. "Sex" was another good one. Eventually, we looked up "Vulva" and "Breasts". 'Twas a good time had by all the kids hovering over the World Book.

I bet you Larry Sanger had a similar experience when he was younger.

Now that I'm a parent, who am I to deny my children the same pleasure of discovery? It seems like this is the one area where everyone is afraid that being informed will somehow make all these children shoot up a school or something. They aren't going to just magically stumble upon "Dutch Pancake (sex act)" or whatever; they're going to be directly searching for the term after one of their friends tells them about it. More than likely, it'll make having "the talk" a lot easier later on if they're already educated; you'll be largely discussing responsibility, rather than technical questions.