It all relates to sex education, which needs to happen in the home and be conducted by the parents - not the public school system. With our two girls, my wife and I did our best to get them to understand that if they were going to have sex in their teen years they better be prepared to drop out of school, forget their social lives and dedicate themselves to raising a baby if they got pregnant. Abortion wasn't discussed since we wanted them to understand the possible consequencs of their actions. We also made it clear we had an open door policy regarding sex talk or anything else for that matter. During their high school years we found that there was an unbelievable amount of confusion and misinformation about sex that was circulating among their peers. Most of these girls didn't have a clue about pregnancy and what causes it, and knew even less about STDs, how they're transmitted and the lifelong consequences that can result with some of them. I believe the thing that made the most significant impression on them was the article and pictures of genital herpes - they didn't want any part of that!
Regarding the sexual activities of the Dutch - it's unlikely that we'll see anything like that anytime soon in the US and I certainly don't agree with it. But looking at the following study comparing the US and Netherlands, it's hard to argue with their results.
Consequences of U.S. and Dutch Approaches to Teen Sex » Sociological Images