"The Supreme Court’s 1973 decision in Roe v. Wade legalizing abortion nationwide potentially fits the criteria for explaining a large, abrupt, and continuing decrease in crime. The sheer magnitude of the number of abortions performed satisfies the first criterion that any shock underlying the recent drop in crime must be substantial. Seven years after Roe v. Wade, over 1.6 million abortions were being performed annually—almost one abortion for every two live births. Moreover, the legalization of abortion in five states in 1970, and then for the nation as a whole in 1973, were abrupt legal developments that might plausibly have a similarly abrupt influence 15–20 years later when the cohorts born in the wake of liberalized abortion would start reaching their high-crime years. Finally, any influence of a change in abortion would impact crime cumulatively as successive affected cohorts entered into their high-crime late adolescent years, providing a reason why crime has continued to fall year after year."