Katie Couric's Notebook: Teen sex

You wouldn't know it from watching the MTV show "Skins," but believe it or not - teen sex is down.

new federal study found the number of teens and young adults - between the ages of 15 to 24 who have engaged in some kind of sexual activity - actually fell six points in the past decade from 78 percent to 72.

Of course, nearly three quarters of them have, so I wouldn't say abstinence is an epidemic. Still, there's something going on - stopping some of them from getting it on.

Maybe it's the fear of sexually transmitted infections. One in four sexually active teens has had one.

Maybe all those abstinence programs did a little bit of good after all.

Or maybe parents today are more comfortable talking to their kids about sex - no euphemisms or "who-ha" talk required.

While they're still at an age between SpongeBob and Skins, have that conversation. It might be the thing that keeps them from going too far - far too soon.

That's a page from my notebook.

I'm Katie Couric, CBS News.