Underdeveloped societies . . . practice little contraception and virtually no sterilization. Consequently, the tendency is to postpone the issue of controlling pregnancy until a later point in the reproductive process, which means that when a couple wishes to avoid children, those methods nearest the point of parturition--abortion and infanticide--are employed.
Industrial societies, on the other hand . . . [use] readily available institutional mechanisms with respect to marriage and [employ] the possibilities of their advanced technology for conception control. Gradually, in the late stages of industrial development, contraception has gained such predominance that it has made [other approaches] unnecessary.
Kingsley Davis and Judith Blake
Many societies of the world prescribe or permit sexual intercourse outside of marriage, but none prescribes conception outside of marriage. Although it is true that placing and caring for an "outside" child constitute more of a problem in primitive societies than they do in advanced societies such as contemporary America, the fact remains that most unmarried couples who engage in sexual intercourse do not wish to conceive a child. Further, many married couples also wish to retain control over the size of their families. The day is long past when pregnancy could be regarded as a natural accident, and all over the world increasing numbers are turning to contracep