The most incisive guide to issues facing the American family today . . . An invaluable resource for anyone wishing to stay on the cutting edge of research on family trends.

-W. Bradford Wilcox
Associate Professor of Sociology, University of Virginia 

Sterile Prosperity

Bryce J. Christensen and Robert W. Patterson

Traditionally, wealthy households were full of children; the biggest family mansions of the nineteenth century were usually well connected with the maternity ward. So why has fertility plummeted among the most affluent couples in modern industrialized counties?

This is the question that received attention in a study by researchers from the University College London and the Centre for Population Studies. These researchers began their investigation fully aware of “the strong positive correlations between wealth and reproductive success that [have] characterize[d] most traditional societies.” The puzzle, then, lies in the way “modernization has brought about substantial increases in personal wealth, [while] fertility in many developed countries has plummeted to the lowest levels in recorded human history.” In the view of the researchers, the patterns of low fertility among well-off couples “contradict evolutionary and economic models of the family that assume increasing wealth reduces resource competition between offspring, [so] favoring high fertility norms.”

To untangle this conundrum, the London scholars analyze ten years of data for 13,176 mothers from socioeconomic backgrounds generally representative of the United Kingdom. These data provide a fresh instantiation of the pattern the researchers wish to probe: “Women [in this study] with relatively high levels of education, high household income, and living in owned versus mortgaged or rented accommodation had fewer children than their same-age counterpoints of lower socioeconomic status.”

The analysis of this pattern finally focuses on the “trade offs” that affluent women face. The decision to pursue higher education, for instance, apparently means delaying or forgoing childbearing for many women. “Levels of maternal education,” the researchers report, “had large negative effects on fertility. This effect is most apparent in the early stages of the study, where mothers holding a university degree had 0.49 fewer children . . . than mothers with the lowest level of qualifications.”

Many well-off women are also apparently choosing to delay or forgo childbearing when they seek employment outside the home: “Maternal employment,” the researchers note, “had strong negative effects on fertility at recruitment [for the study] and on the rate of fertility increase over the study period.”

Many affluent women in the study also chose to have few children because of the perceived difficulty of meeting the financial obligations of a larger family. The researchers adduce “clear evidence that high fertility comes at a significant economic cost in modern populations.” What is more, “relatively wealthy and well-educated mothers perceive greater economic costs to raising a large family.” Further parsing of the data suggests that it is affluent couples who are most likely to worry about such costs when considering a third or fourth child. “When contrasting one- and two-child families,” explain the researchers, “higher income and education reduce the perceived economic costs of reproduction. However, when considering mothers with more than two offspring, relatively high socioeconomic status appears to hold increasing disincentives to further reproduction, while low-income and low-educational-attainment mothers pay no additional penalty.”

This study does indeed clarify the dynamics of low fertility among affluent couples. What it does not do is dispel concerns about the long-term cultural consequences when affluent couples—those with the most financial resources for childrearing—increasingly leave the challenge of childbearing to couples who are less well off.

(David W. Lawson and Ruth Mace, “Optimizing Modern Family Size: Trade-offs between Fertility and the Economic Costs of Reproduction,” Human Nature 21.1 [March 2010]: 39–61, emphasis added.)