I'm with Chad on being a smart parent here and I think he's right on the money about how parents should approach filtering the infomation that reaches their kids. I don't think there's a magic number when a kid should see tits or when he should find out Jesus Santa isn't real, but I think it should generally coincide with when your kid starts to be curious about it. If your kid is curious about something -- pretty much anything -- he'll learn what he needs to know. He can learn it with parental guidance or some other way, but he'll learn it.
As for the Government sanitizing the web you guys gotta be ---smurfing--- crazy. How could anyone ever want that? If you're a liberal, you should be a 1st Amendment person. If you're a conservative you should be a "stay the ---fudgesicle--- off my back Government" person. Let the market decide. If there's a market for it let the porn stay on the internet. If there's a market for filtering software, filtering software will (and has) emerge.
People who think that freedom of speech is all well and good except when people are being offensive have never given the bill of rights serious thought. Speech or expression that the majority of people find agreeable doesn't need protection....it isn't threatened. The WHOLE point of the 1st Amendment is to protect the your right to express unpopular views, to be offensive, to be disagreeable, without fear of being silenced.
Anyway....America is a bunch of puritans and it's unhealthy. We've turned sexuality and the human body into such a crazy taboo that people turn deviant while they think about it and want it and lust after it, but are near forced to pretend otherwise. We end up with a society that's off the charts with rapists, child molestors, etc. Lighten up. It's just a penis and a vagina.