Freakonomics, abortions and crime

Orson Scott Card discusses Freakonomics the discovery of correlations, causes and effects that completely disagree with what is usually considered common knowledge. He uses correlations between crime rates, abortion and promiscuity as a prime example.

Even if you disagree (and I'm sure most people will, because the conclusions are quite disturbing), it's extremely thought provoking and should be read by as many people as possible.