Has use of lead-free gas decreased the crime rate?

A lengthy treatment of the abortion question:

http://www.isteve.com/Freakonomics_Fiasco.htm

It's too late to give a good summary right now, but basically, it comes down to the question of "who gets abortions?" and counter-intuitively, it's not the thoughtless, last-minute-birth-control people, but rather people who take a careful look at the cost:benefits of unwanted pregnancy, and so terminate--and they are usually smart, non-criminal types.

I agree that it sounds plausible, but it seems like his math just might not hold up. If you want to see a detailed analysis of the issue, check out http://post.economics.harvard.edu/faculty/miron/papers/Comme....

Wouldn't more abortions mean less unwanted children mean less screwed up children mean less crime? Sounds plausible to me -- the main issue is whether this is a big effect or a small (negligible) effect.

This lead thing, on the other hand, is silly. It's just a correlation and then they guess there is a causation. Plus some statistics, but people get those wrong all the time, and they still allow for some other thing to cause both.

It's especially silly because the thing being explained is so easy to explain. Crime rates are lower in more modern times? Really? Wow. Maybe it's because children are beaten less often, and thus less angry, or any of the many other ways we've become more civilized.

Even a correlation with air pollution is pretty easy to explain this way. Maybe the same states that regulate air pollution aggressively are also progressive in other ways.