The advent of the second half of the twentieth century brought with it a sweeping revolution in societal attitudes to abortion. In nation after nation the call for abortion-law reform became irresistible. Profound and widespread legal liberalization began to shape the landscape in a way that would make this period entirely discontinuous from that of the nascent nation states of the nineteenth century. Liberalization, it must be stressed, did not always imply that abortion was available without restrictions, but, in every place in which the liberalization process arose, it wrought dramatic changes, allowing for abortion under a broad range of circumstances that previously had been the subject of prohibition. Thus, in the quarter century from the mid 1950s to the early 1980s, an unprecedented avalanche of abortion-law reform – never contemplated in the first half of the century – touched the lives of approximately 60 percent of the world's population.

A number of contributing forces propelled these tectonic shifts. The horror of the loss of women's lives through improper care that too often accompanied illegal abortion was undoubtedly an important factor. The burgeoning of more relaxed attitudes towards sexuality and reproductive functioning was another cause, the impact of which cannot be underestimated. These new attitudes themselves were intertwined inextricably with the arrival of safe and reliable birth-control methods, which, for the first time in human history, allowed for a great deal of control over procreation.