Tim Harford's explanation for the rise in teenage oral sex may be rational for boys, but it doesn't explain the cultural shift in behavior among the young ladies.
See my previous post for a review of the recent discussions.
Harford cites research that hypothesizes an explanation: if teenagers really did think about the consequences of their actions, they would have less risky sex if the cost of risky sex went up.
The problem is that while this may be spot on for men, this doesn't explain women's behavior entirely.
I get that the motivation to have sex for women (say pleasure, peer pressure, wanting people to like you etc.) remains the same and if sex gets more risky then they may move on to less costly behaviors.
This may even be motivated by men wanting to avoid the more risky act.
But, as Caitlin Flanagan asks: How did we go from a middle-class teenage girl (fictional but broadly accurate) who will have sex only if it's with her boyfriend, and only if her pleasure is equal to his, to a middle-class teenage girl (a gross media caricature reflective of an admittedly disturbing trend) who wants to kneel down and service a series of boys?
In fact, in some senses, for women, this behavior seems even MORE risky. At least according to this evidence, regardless of the act, women have gone from a few (even one) intimate partner with whom to share sexual acts, to many random partners. Instead of Suzy going steady with Dan and speculations that they are (ahem) involved, we have Suzie's All-She-Can-Eat Fellatio Emporium. This can't be a positive evolution.
It seems to me that Harford's analysis is a little gender one sided.