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.
That's what I was driving at, more or less. So I agree. Abstinence shouldn't equal ignorance of basic biology, or what (at least I believe) sex should be about.