I was always pretty skeptical of the result. A few things to keep in mind:
1) Black men are much more likely to commit a crime.
2) Black women are much more likely to get an abortion.
3) The study was done at a time when crime rates were going down.
If you try to study a factor that results in fewer of 1 because of the actions of 2 while 3 is also happening (perhaps for completely different reasons - enforcement, incarceration, etc) you can get a result like that. I'm sure the people behind the study thought of that and tried to adjust for it. But, let's face it, there is really no way to discuss this topic without finding yourself in a very dangerous minefield.