A former university academic dean, I know of hard-nosed Calculus professors who started off their introductory class by saying to the students, "Look at the person to the right of you and the one to left of you." Then they continued, "One of you is going to fail this class." Then to add hard evidence, the professors asked for a show of hands of those who were taking Calculus for the first time, next they would ask how many were taking it for the second time, and finally how many were taking it for the third time.
By this point most of the students were beginning to get the message that Calculus is a really tough subject and the odds of flunking are high if you fool around and don't develop the discipline to study hard. Students got the message; it's a costly proposition to fail Calculus, a gateway subject, if your ambition lies in the more lucrative disciplines of the hard sciences. Chances are, if you can pass Calculus, you won't earn your living asking, "Would you like fries with that?"
Sadly, the opponents of abstinence education don't want an equally tough approach to the realities of sexual activity. Their mantra is: "kids are going to experiment, so give them condoms." But given the unforgiving nature of a sexually transmitted disease such as genital herpes – once you get it, you've got it for life – not to mention some of the others like human papillomavirus (HPV) that increase the odds of cervical cancer, or the lengthy and unrelenting demands of taking care of an unplanned infant, I think it is only fair for the kids to know exactly what their odds are when they are given condoms and told "if you're going to do it, use protection."
To answer this question factually, we need to look at the outcomes to see just how effective condoms are, not theoretically in a testing laboratory, but in actual usage by teenagers. What the data clearly show is that in real-world conditions, condoms work much of the time but they certainly don't work all of the time. Now there's a comforting thought for any young girl when she's contemplating the prospect of (a) putting her hopes and dreams of a college education on hold in order to care for a baby she wasn't ready for, or (b) the never-ending discomfort and embarrassment of dealing with herpes, a disease she'll have to cope with for the rest of her life and one which she could pass on to anyone she is intimate with; she can even pass the disease to her own baby.