According to one study, a potentially interesting factor in the decline in teen pregnancy wasn't a curriculum or sex education. It was an MTV show about teens being pregnant. Seriously. I was not expecting that.
While it has drawn some valid criticism for salacious portrayals that stigmatize real pregnant teens whose lives aren't like those of camera-seeking reality stars, because of the data, I don't think we can dismiss it out of hand.
There are far better ways to help de-stigmatize teen pregnancy while simultaneously decreasing the numbers of them. You can read more on the negative effect on existing teen moms. If you'd like to get some great perspective from a real teen mom, go read Gloria Malone.