Why we don't have more sex

As I've already posted this morning on economics and on sex (well, sex-changes) it seems appropriate to post here the economist's answer to that age-old question "Why don't we have more sex?"

Yeah, I know, as Tonto told the Lone Ranger, "What's with the we, white man?"

Anyway, the question is posed thus:

...all forms of consequentialism have a great deal of difficulty interpreting sexual behavior. To put things short, there is an inexplicable shortage of sex. Given that studies show that women and men enjoy it more than most other activities (on average, not on the margin I'll grant), and given its intrinsically low cost, it appears that even a crude approximation of a utility maximizing person would probably spend much more time having sex than most do. Do you know of any economic discussion of this?

So here you go, the top twelve reasons given by economists for why we don't spend more time having sex, starting here.

Probably not the right time to point out that it's a rare example of an economist coming to a conclusion. Pun intended.