Delaying intercourse until teens are older is not a naive proposal. While not a majority, they are living proof that teens can control their sexual desires. It is not a big leap from teenagers being unable to control their sexual desires to being unable to control their hate, greed, anger, and prejudice. Teenagers are willing to discipline themselves for things they want and desire and are convinced are beneficial. Girls get up early for drill team practice.
Boys train in the off-season with weights to get stronger for athletic competition.
Our teens can also be disciplined in their sexual lives if they have the right information to make logical choices. Saving sex for marriage is the common sense solution. In fact, it is the only solution. We don't hesitate to tell our kids not to use drugs, and most don't. We tell our kids it's unhealthy to smoke, and most do not.