Seconded. The result that made the book popular- abortion reduces crime- was so strongly contested by Steve Sailer (debate here) and others that I'd call it refuted.

In the book, Levitt makes a comment at some point that he wasn't good at the mathematics side of economics, but was great at the unconventional thinking side. That set my alarms blaring, because thinking unconventional things is no credit when you screw up the math. Which Levitt appears to have done at least once.