It would be interesting to see some more stats on number of sexual encounters by abstinence-only teaching/none-or-other methods. I mean, per Wikipedia, pregnancy rates using only a condom are on average the worst at 18%; a condom user (well, condom user’s partner) would have to have sex 8 more times than someone who has a single, non-protected encounter to be at the same risk rate. HIV/AIDs infection rate lowest reduction is 80%, so that’s roughly the same sort of difference. (I think, anyway; statistics are really not my strong suit). Which is a worrying figure, especially compared to the numbers you’ve quoted.