"More Sex Is Safer Sex."

That's the name of the new book by Steven E. Landsburg and the name of his 1996 article arguing "that H.I.V. would spread less quickly if relatively chaste people each took on a few more sexual partners":

At a given bar on a given night, he wrote, these disease-free singles would then make the pool of sexually active adults safer. The article was based largely on an academic paper by another economist, Michael Kremer, theorizing that the spread of AIDS could be slowed in England if everybody with fewer than about 2.25 partners got around a bit more

The link is to a book review by David Leonhardt, who doesn't think much of what he calls the the economists' "imperialist movement" -- intruding their analysis into all sorts of human affairs:

[The book is] short on the nuance that comes from real human stories. Landsburg’s characters tend toward the hypothetical... and his arguments, as he puts it at one point, can sound like “idle Sunday dorm-room chitchat.”

This problem plagues many of the new economic imperialists: like the overly chaste singles who are supposedly contributing to the H.I.V. epidemic, they don’t get out enough. They are asking good questions about epidemiology and psychology, but they are not spending much time with epidemiologists and psychologists, let alone with the people who are the subjects of their academic research.

IN THE COMMENTS: One of the coolest things about blogging: the author of the book appears and defends himself (in a thread that hilariously begins with the comment "He was great on Barney Miller").