Well, Sarah's daughter was not a grown woman when she got pregnant. She was a 17 year old teen ager. She took the same risk that kids who are taught abstinence are prone to take. And, she is now a part of the statistics showing the rise of teen pregnancies in kids who are taught sex ed from an abstinence only perspective. There have been several studies that show that kids who are taught abstinence have sex at the same age and the same rate as kids who are taught a comprehensive sex ed. They are just less inclined to use birth control if they are taught abstinence. And it makes perfect sense. "Wait until marraige" is a moral dictate. Therefore, there is a judgement attached. Implied in the absitinence only message is if you don't wait until marraige, you are amoral and bad. Therefore, the kids who get the abstinence only message don't want to be judged as bad, so they go out of their way to hide the fact that they are sexually active...which means not going into a store to purchase condoms, not asking parents to take them to the doctor to get birth control, not visiting a clinic to get it on their own, etc. The result is increased teen pregnancies...something that we are again seeing with the abstinence only programs. We are also seeing an increase in STDs as a result.
Teaching about birth control and sexuality is simply imparting knowledge. Abstinence only is adding a moral judgement to that knowledge that has no business being there. Morality is a personal condition.