I sincerely doubt there are more than a tiny handful of girls old enough to get pregnant who don’t know how it happens and how to prevent it. It is not a matter of education. It is a matter of a culture that doesn’t care. At best it is ignored, at worst it is glorified. When I taught high school the girls got all excited when one of their peers got pregnant. The reality of a baby didn’t set in until well after the fact, and frankly, the girls who are getting pregnant are not the sorts who learn from other people’s mistakes.
Fast forward to one of the few couples who married (not a nice story though since he and his family accused the girl of having someone else's baby) - on a follow up show this couple said they were NOT using any sort of birth control. Even though they knew they were quite capable of conceiving, they were just too stupid/lazy/choose your own adjective to obtain free birth control.
MTV's Teen Mom: Season 1 (reality show)
$26.99 at Amazon...
"In 16 and Pregnant, they were moms-to-be. Now, follow Farrah, Maci, Amber, and Catelynn as they face the challenges of their first year of motherhood."
Obviously, we need remedial sex ed classes...