Sex Differences in the Association of Family and Personal Income and Wealth with Fertility in the United States
Evolutionary theory predicts that social status and fertility will be positively related. It also predicts that the relationship between status and fertility will differ for men and women. This is particularly likely in modern societies given evidence that females face greater trade-offs between status and resource acquisition and fertility than males. This paper tests these hypotheses using newly released data from the 2014 wave of the Survey of Income and Program Participation by the US Census, which has the first complete measures of fertility and number of childbearing partners for a large, representative, national probability sample of men and women and also contains comprehensive measures of economic status as measured by personal and family resources, including income from all sources and all assets. Multivariate analyses show that personal income is positively associated with total fertility and number of childbearing unions for men only. For men, personal net worth is positively associated with number of childbearing unions; it is also positively associated with fertility for married men with a spouse present. These findings support evolutionary predictions of a positive relationship between status, access to mates, and reproductive success for males. Whereas personal income and personal net worth are negatively associated with total fertility and number of childbearing unions for women, family income (net of personal income) is positively associated with total fertility for women. For married men living with a spouse, family income (net of personal income) is negatively associated with total fertility. These findings are consistent with evolutionary theory given the existence of greater trade-offs between production and reproduction for women in an advanced industrial society. For women and men, family net worth (net of personal net worth) is negatively associated with number of childbearing unions and fertility. Implications are discussed.
KeywordsWealth Income Fertility SIPP Status Sex differences
- Borgerhoff Mulder, M. (2019) Bateman’s principles & the study of evolutionary demography. In O. Burger, R. Lee and R. Sear (Eds.), Human evolutionary demography. Retrieved 9/18/19 from https://osf.io/p59eu/.
- Brewster, K. L., & Rindfuss, R. R. (2000). Fertility and women's employment in industrialized nations. Annual Review of Sociology, 26(1), 271–296.Google Scholar
- Coleman, D. A. (2000). Male fertility trends in industrial countries: Theories in search of some evidence. In C. Bledsoe, S. Lerner, & J. I. Guyer (Eds.), Fertility and the male life-cycle in the era of fertility decline (pp. 29–60). Oxford: Oxford University Press.Google Scholar
- DiPrete, T., Morgan, S. P., Engelhardt, H., & Pacalova, H. (2003). Do cross-national differences in the costs of children generate cross-national differences in fertility rates? Population Research and Policy Review, 22, 439–477.Google Scholar
- Dye, J. L. (2008). Fertility of American women: June 2008. Current Population Reports, P20–563. Washington, DC: US Census Bureau.Google Scholar
- Goodman, A., & Koupil, I. (2010). The effect of school performance upon marriage and long-term reproductive success in 10,000 Swedish males and females born 1915–1929. Evolution and Human Behavior, 31(6), 425–435.Google Scholar
- Goodman, A., Koupil, I., & Lawson, D. W. (2012). Low fertility increases descendant socioeconomic position but reduces long-term fitness in a modern post-industrial society. Proceedings of the Royal Society of London B: Biological Sciences, 279(1746), 4342–4351.Google Scholar
- Henry, J., Helm Jr., H. W., & Cruz, N. (2013). Mate selection: Gender and generational differences. North American Journal of Psychology, 15(1), 63–70.Google Scholar
- Hopcroft, R. L., & Whitmeyer, J. M. (2010). A choice model of occupational status and fertility. Journal of Mathematical Sociology, 34(4), 283–300.Google Scholar
- Hrdy, S. B. (2000). The optimal number of fathers: Evolution, demography, and history in the shaping of female mate preferences. In D. LeCroy and P. Moller (Eds.), Evolutionary perspectives on human reproductive behavior (pp. 75–96). Annals of the New York Academy of Sciences 907.CrossRefGoogle Scholar
- Johnson, K. M., & Lichter, D. T. (2016). Diverging demography: Hispanic and non-Hispanic contributions to US population redistribution and diversity. Population Research and Policy Review, 35(5), 705–725.Google Scholar
- Kaplan, H. S., & Lancaster, J. B. (2003). An evolutionary and ecological analysis of human fertility, mating patterns, and parental investment. In K. W. Wachter & R. A. Bulatao (Eds.), Offspring: Human fertility behavior in biodemographic perspective (pp. 170–223). Washington, DC: National Academies Press.Google Scholar
- Leupp, K. (2019). Bargaining bonus or breadwinning burden? Wives’ relative earnings, childrearing, and depression. Sociological Perspectives. https://doi.org/10.1177/0731121419842132.
- Nisén, J., Martikainen, P., Myrskylä, M., & Silventoinen, K. (2018). Education, other socioeconomic characteristics across the life course, and fertility among Finnish men. European Journal of Population, 34, 337.Google Scholar
- Oppenheimer, V. K. (2000). The continuing importance of men’s economic position in marriage formation. In L. J. Waite et al. (Eds.), The ties that bind: Perspectives on marriage and cohabitation (pp. 283–301). New York: Aldine de Gruyter.Google Scholar
- Trivers, R. (1972). Parental investment and sexual selection. In B. Campbell (Ed.), Sexual selection and the descent of man, 1871–1971 (pp. 136–179). Chicago: Aldine de Gruyter.Google Scholar
- Wilson, E. O. (1980). Sociobiology. Cambridge: Harvard University Press (Originally published in 1975).Google Scholar
- Zhang, L. (2011). Male fertility patterns and determinants. Springer Series on Demographic Methods and Population Analysis 27. Dordrecht: Springer.Google Scholar