The problem isn't teaching abstinence, it's a failure to properly explain the risks associated with having sex.
There is no reason why you should keep you child ignorant of the facts of life. You can do that without saying "have safe sex". You say, we don't want you to have sex before marriage, and this is why.
Seems pretty simple to me.
It's more than about the risks, it's about the nature of sex.
People will take risks for fun. That's part of who we are. Ever been skiing? How about racing a car, or a horse. Even playing a game of flag football is taking a risk for fun.
But sex isn't about fun, it's about creating a bond between yourself and a member of the opposite sex (clarified for those of us from Mass.). If you don't want to marry him/her, don't sc*** him/her. It's that simple.
And if he doesn't want to marry you, why would you give him your body as a gift? He doesn't deserve it.
Shalom.