Two American economists, Donohue and Levitt, have argued that the complete legalization of abortion in the US between 1967 and 1973 resulted in a significant drop in the crime rate from the 1990s onward. As Levitt reasons, "Legalized abortion led to less unwantedness; unwantedness leads to high crime; legalized abortion, therefore, led to less crime."1
However, this argument has been challenged by other economists, who note several errors in Donohue and Levitt's calculations and findings. Some contend that the decreased crime rate can be linked to the simultaneous decline of the crack-cocaine epidemic.2 Others challenge Donohue and Levitt for failing to separate criminals into age categories, since the decrease in crime actually occurred among older cohorts rather than those born after the legalization of abortion. In fact, crime has been increasing among these younger cohorts.3 Another challenge to Donohue and Levitt's findings is that since abortion was legalized in the UK, crime rates there have risen.4
Researchers have also pointed out that the rise in abortion since its legalization has increased the incidence of single motherhood,5 in part because treating abortion as a method of birth control enables men to opt out of commitment. Since the children of single-parent families are at higher risk of criminal behaviour than those of two-parent families, it is more likely that the rise in abortions has increased, rather than decreased, the crime rate. Additionally, high-risk mothers are less likely to abort than low-risk mothers.6
Much of the research done in the past decade casts doubt on whether Donohue and Levitt's supposed link between abortion and falling crime rates exists at all.