You are so incredibly mistaken. I have raised or am raising 6 children and have taught them abstinence with much success. It is absolutely false that kids can't be taught abstience, believe in it, and follow it. The prerequisite is that the parents must have solid reasons for teaching it, reasons that transcend the potential for disease and pregnancy. It's much more effective when the reason is based in deeply held spiritual beliefs. The teachings need to be regular and consistent. The children need to be taught the joys of sex in marriage. They need to see sex as beautiful and something God wants them to wait for. There are kids who feel that way and who abstain. I realize that some kids will not abstain, even if they were taught by parents to abstain.
MY 19 year old daughter, when she was a Jr. in High School, once told my wife how disgusted she was that "every boy" she meets, thinks she should give him oral sex. She was repelled at the thought and never had sex with anyone. This meant fewer dates and boy friends, I suppose.
I'm not saying we've had 100% success in this regard as parents, but there is no doubt that our teachings and the teachings of our church have gone a long way to influence our kids to be sexually pure.
To those parents who believe in the sanctity of sex and the importance of waiting until marriage, don't give up! Our kids are strong enough to swim upstream against the social currents. Teach chastity to your children with the greatest conviction of your heart and soul!