The lowest-known proportion childless among ever-married women is less than 3 percent for a Hutterite religious community in North America with virtually universal early marriage of women (Veevers 1972). Low figures occur where a population has high proportions married in their early twenties and does not use family planning or abortion to delay the first birth. Conversely, high proportions of childless are related to late marriage, low proportions marrying, and use of birth prevention.
The early peak in childlessness, for women born in the 1900s, was associated particularly with childless marriages, rather than a fall in the proportions marrying. The Great Depression and World War II had more impact on childbearing than on marriage, but couples who postponed having children until better times risked remaining permanently childless if they delayed too long. Staying childless within marriage did not depend on innovations in methods of family limitation, but on early and widespread use of methods already known. Gigi Santow (1995) considered that coitus interruptus was "instrumental" in the trend to lower birth rates in Western countries and that it was in common use in all European countries during the early decades of the twentieth century. Sexual abstinence and abortion were also important, and low coital frequency may have been as well (Santow 1995; Szreter 1995). The passing of the effects of economic depression and war later facilitated a decline in married childlessness to relatively low figures, especially among the cohorts that produced the baby boom after World War II.
Changes in the proportions of people who marry have also shaped trends in childlessness. A major twentieth century development was the marriage revolution—a trend toward earlier and more universal marriage in Western societies, associated with a weakening of economic constraints. For example, in France, 11 percent of women born in 1900 had never been married by their fiftieth birthdays, compared with 7 percent of women born in 1940 (Toulemon 1996). A similar fall, to somewhat lower minimum figures, occurred in the United States (Haines 1996). The marriage revolution reduced the proportions of single and childless people and contributed to social expectations, peaking in the 1950s and 1960s, that most people would marry and become parents.
The subsequent resurgence of childlessness occurred in the context of the end of the marriage revolution, bringing a decline in the proportions marrying and a rise in age at marriage. The increasing educational attainments of women reinforced the trend toward delayed marriage, as well as supporting roles and value systems that represent alternatives to motherhood. Later marriage decreases the time during which pregnancy can occur, brings better knowledge of contraception, and strengthens the likelihood of a commitment to a childless lifestyle (de Jong and Sell 1977). Later marriage also increases the likelihood of low fecundity and difficulties in achieving a viable pregnancy. The revival of childlessness was further associated with the availability of more efficient methods of family limitation, especially the contraceptive pill and wider recourse to safe methods of sterilization and abortion.
For cohorts born since the 1950s, the distinction between married and unmarried childlessness has become less clear because consensual unions have attained greater acceptance in many countries, where higher proportions of children have been born outside formal marriages. Some authors perceive a global transformation of the matrimonial system in which relationships are merely the expression of individual choices, without societal regulation or concern.
Social scientists, however, are still debating the relative importance of voluntary and involuntary factors in the upturn in levels of childlessness, although individual self-fulfillment and freedom of choice have been seen as important (Poston and Kramer 1983; Carmichael 1995; Lesthaeghe 1998). In the United States, Dudley Poston and Erin Gotard (1977, p. 212) attributed the early part of the rise in childlessness mainly to voluntary factors "linked to broader changes in the fabric of society regarding fertility control, contraceptive technology, female work preferences and patterns, and sexual and family norms." They saw as a key trend the equalization between the sexes of opportunities for nonfamilial roles. Other commentators, however, consider the workplace insufficiently supportive of women who would like to combine employment and motherhood: equality of opportunity in employment does not necessarily entail adequate support for childbearing and parenting. Others commenting on the rise of childlessness emphasize the long-term consequences of delaying family formation, given that many women do not wish to have a child until they are in their thirties, when the likelihood of fertility problems is greater.
Overall, there has probably always been a mixture of voluntary and involuntary factors in childlessness. It cannot be assumed that in the past marriage and family formation were universally desired, or that in the present, all are able to achieve their particular marital and reproductive goals. Nor is there an absolute distinction between voluntary and involuntary outcomes, especially since childlessness often results from delaying childbearing, rather than from a single decision never to have children (Poston and Trent 1982; Morgan 1991).
In West German opinion polls since 1953, less than 5 percent of women said that they did not want to have children (Schwarz 1986), but this is far fewer than the actual proportions remaining childless. Similar surveys in other European countries mostly found that only 2 to 5 percent of young women did not want any children (Coleman 1996). Respondents may wish to give the appearance of conforming to traditional family norms, but postponements strengthen preferences for a lifestyle without children.
Overall, the rising prevalence of childlessness is one aspect of the diversity of life-cycle experience among people of reproductive age. It arises from a combination of varied phenomena including: the decline of social pressures to marry and bear children, inability to find a partner, lack of interest in finding a partner, insufficient commitment in relationships, concern about the durability of relationships, concern about the prospects for children in insecure environments, financial problems and constraints, difficulties in combining parenting and employment, dislike of children, postponement of childbearing, declining fecundity at older ages of family formation, and pursuit of careers and material consumption.