The five states that allowed abortion in 1970 (three years before Roe v. Wade) experienced declines in crime rates earlier than the rest of the nation. States with high and low abortion rates in the 1970s experienced similar crime trends for decades until the first cohorts
exposed to legalized abortion reached the high-crime ages around 1990. At that
point, the high-abortion states saw dramatic declines in crime relative to the
low-abortion states over the next decade. The magnitude of the differences in the
crime decline between high- and low-abortion states was over 25 percent for
homicide, violent crime and property crime. For instance, homicide fell
25.9 percent in high-abortion states between 1985 and 1997 compared to an increase
of 4.1 percent in low-abortion states. Panel data estimates confirm the strong
negative relationship between lagged abortion and crime. An analysis of arrest rates
by age reveal that only arrests of those born after abortion legalization are affected
by the law change.