Baby Nudges: How Social Influences Shape Fertility Choices

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From 2010 to 2026, Ultra-Orthodox Jews in the New York City metro area averaged 7.5 children born per woman. During the same period and in the same metro area, college-educated, native-born non-Hispanic white women averaged 1.58 children per woman. In Ohio, Amish communities average around 6 children per woman—while Ohio itself has been below 2 children per woman for many years.

These contrasting trends highlight how people inhabiting the similar economic worlds end up with radically different families. While nobody would dispute that economic and material factors may influence birth rates, there is good reason to believe that there is much more to the story. Clearly, culture matters. The differences in birth rates between various groups of people are not simply a function of differences in child care affordability or household incomes and parental opportunity costs; they are at least partly a function of differences in cultural norms and values—and those norms and values may be changing.

Unfortunately, “culture” has long been used as a catch-all term: any variation in fertility not explained by variables we understand well (like housing costs, contraception, child mortality, or marriage rates) too often ends up lumped together as “culture.” Why do Ultra-Orthodox Jews have higher birth rates? Because of their culture. The Amish? Culture! Latter-Day Saints in Utah? Apparently, again, culture. This “black box” approach to defining culture obscures more than it illuminates. Where does this nebulous “culture” come from? What are its constituent parts? Why do members of some cultures reproduce more despite the same material circumstances as their neighbors? What is it about some cultures that makes them more pronatal and child centered than others?

Surprisingly little prior work has tried to untangle exactly which values and attitudes matter most for shaping family life. This is not to say scholars have not investigated “non-material” factors shaping fertility. In fact, scholars have long pointed to strong effects from fertility norms within social groups. If your family member, friend, or colleague has a baby, you are more likely to have one, too. This effect is not limited to real-life friends: television shows that depict smaller families have also predicted fertility decline. Negative portrayals of teen moms may also reduce fertility. At the same time, the full picture of how “culture” interacts with fertility has to include more than contagion of behavior; otherwise norms would never change.

Here again, scholars have not been absent, studying how Papal speeches shape Catholic fertility, how prestigious godparenting opportunities shape family size among the Georgian Orthodox, and how a sense of historic Irish national identity may influence fertility. Nonetheless, besides contagion, role modeling, and religion, appeals to culture and fertility have often been used to explain gaps in research and residuals in models, rather than hard evidence. We know fertility is contagious, but we do not know what exactly is being “caught.” We know religious leadership can sometimes influence fertility, but we have no idea what it is about that leadership that has an effect. In this report, we begin the work of opening the black box of fertility culture. We explore the specific factors across and within societies that lead some people to have many more children
than others.

We used a survey of nearly 10,000 people spanning over a dozen countries from the U.S. to Israel to Korea. The survey asked about a wide range of family attitudes to explore how individuals who are sometimes called “cultural elites” (i.e., celebrities and other public figures of high social visibility) shape fertility desires, how peers influence each other, how parents and religious leaders encourage fertility, and other specific cultural norms and practices. Most of our survey covered questions that have rarely, if ever, been surveyed cross-nationally, or have not been surveyed in a research program that also studied fertility. As a result, we can present first-of-a-kind evidence on what specific cultural norms typify successful pronatal cultures.

To supplement this survey, we also created and analyzed a database of family behaviors among individuals who are seen as current and historic elites (i.e., socially visible people with Wikidata or Wikipedia pages) in several countries, exploring the role of social and cultural elites in shaping family culture. This report amounts to a bold experiment: can we study rarely investigated facets of social and cultural influences on family culture and fertility ideation using a survey instrument across a wide range of countries? We find that the answer is: yes. Our survey has yielded reams of interesting results, which readers can browse in the interactive online tool associated with this report.

Our findings are of enormous relevance to anybody wondering what is going on with family formation among their friends, family, parishioners, neighbors, or countrymen. First, we find resounding evidence that peers do matter to fertility. We replicate findings of fertility contagion from the academic literature and show that, across cultures, perceptions of peer support for childbearing matter a great deal. Likewise, we find evidence that public figures and celebrities influence fertility behaviors—though not as much as prospective grandparents might. Meanwhile, the frequency with which religious leaders emphasize family turns out to not be especially influential in our sample, much to our surprise (though regular religious participation remains important).

We also demonstrate new links between specific kinds of norms and attitudes and fertility. For example, we show that risk preference has a meaningful relationship with fertility, while “pronatal general norms” turn out not to have strong ties. In the societies we studied, a sense of general obligation to have children is not an important family formation motivator, even as personal enjoyment of children or parenting is.

Overall, our work barely scratches the surface of the relationship between culture and fertility, yet it nonetheless identifies many productive avenues where pronatalists might start talking to friends and family about the beauty and value of having and raising kids.

About the Authors

Lyman Stone is Senior Fellow and Director of the Pronatalism Initiative for the Institute for Family Studies. He and his wife Ruth have four children and live in Kentucky.

Peter Foreshaw Brookes is a Research Associate at the Institute for Family Studies’ Pronatalism Initiative. He and his wife have one child and live in England.

Jason Carroll is the Marriage and Family Initiative Director at the Wheatley Institute at Brigham Young University. He is also a Senior Fellow at the Institute for Family Studies. He and his wife Stefani have 5 children and live in Utah.