[PhiPsiRuss]

I was watching The Daily Show, and they had the author of Freakonomics on. He was making the case that unwanted children are far more likely to become criminals. After abortion was legalized, fewer unwanted children were born. The national crime rate began to drop when these unwanted children would have begun to commit crimes.

I'm a little bit skeptical that this is the sole reason, but its a compelling argument.