Statistics on trends in childlessness over time suggest three main features: high levels of childlessness for women born in the 1900s, declining levels for women born between about 1910 and 1949, followed by an increase among those born after 1950 (Figure 1). The changes reflect the impact of different social circumstances during their reproductive spans. Adding thirty to the birth year indicates the time when a female birth cohort, composed of women born in a given period, would have been in the midst of their potential childbearing years.
The peak figures for women born in the 1900s were related to the effects of the Great Depression on family formation, which led to delays in childbearing that some never made up, especially since World War II followed closely. Although figures varied among countries, 20 to 25 percent childless were typical peaks from which the subsequent decline in childlessness ensued.
The decline, among women born in the next four decades, reduced the prevalence of childlessness to between 10 and 15 percent, the lowest figures being for women born in the 1940s. The change was associated with economic and social conditions that fostered rises in the proportions marrying and having children, most notably in countries, such as the United States, that experienced protracted baby booms for fifteen or more years after World War II. Thus, the cohorts that became the parents of the baby boom generation had the lowest proportions of childless. The period of the decline in childlessness, like the boom in marriage and childbearing with which it was associated, was exceptional and relatively short-lived.
The childbearing years of the cohorts born between 1910 and 1949 largely preceded the changes that became particularly evident in the 1980s, toward greater social acceptance of family diversity, and weakening social expectations that individuals should marry and become parents (van de Kaa 1987; Lesthaeghe 1998). A return to higher levels of childlessness has been occurring among women born since the start of the 1950s. The trend is commonly associated with lower proportions marrying and with birth rates falling below replacement level, that is, below the level needed to maintain population numbers. Sharp increases in childlessness have been evident in the United States, England and Wales, Australia, Denmark, and Sweden. Some countries, such as France and Italy, have experienced a more delayed revival of childlessness (van de Kaa 1997; Toulemon 1996). Estimates of childlessness for cohorts still in the reproductive ages are necessarily tentative, but social researchers generally agree that the resurgence is an ongoing trend, with figures around 20 percent forecast for cohorts currently of reproductive age (Hakim 2001; Merlo and Rowland in press).