The new reproductive technology was adopted quickly, and on a massive scale. Marital and fertility patterns changed with similar drama, at about the same t he use of birth-control pills at first intercourse by all unmarried women jumped from 6 percent to 15 percent in just a few years, and probably much more among sexually active unmarried women. During the same period, births per unmarried woman roughly doubled for whites, while the fraction of white unmarried women rose about 30 percent. For black unmarried women, the birth rate actually fell by between 5 percent and 10 percent, but this was offset by an increase of about 40 percent in the number of unmarried black women. The shotgun-marriage rate itself declined only gradually, but that is not surprising.
Social conventions change slowly.
It took time for men to recognize that they did not have to promise marriage in the event of a pregnancy in exchange for sexual relations. It may also have taken time for women to perceive the increased willingness of men to leave them if they demanded marriage. One final puzzle, however, requires explanation. The black shotgun-marriage ratio began to fall earlier than the white ratio and shows no significant change in trend around 1970. Here, federal welfare benefits may play a role.