A study published in the Journal of Marriage and Family has found that political identity is increasingly influencing the number of children young adults desire to have. Spanning three decades, the research found that young Republicans consistently expressed a stronger desire for larger families compared to their Democratic counterparts, with this gap widening over time. By 2019, Republicans wanted more children than ever compared to their Democratic peers, a pattern the researchers believe may affect demographic trends in the United States.
The study was motivated by a growing interest in how identities shape personal choices. While many studies have looked at how factors such as religion, gender roles, and socioeconomic status impact family size, political identity has been less frequently explored. However, political identity has become a significant part of how people see themselves, especially in the U.S., where party affiliation influences not just political views, but also lifestyle choices and social norms.
With fertility rates falling and political polarization on the rise, the researchers sought to understand if young adults’ political beliefs were linked to their fertility desires, potentially revealing new insights into future demographic trends.
To investigate, researchers Heather Rackin and Christina Gibson-Davis analyzed data from the Monitoring the Future (MTF) study, which surveys 12th graders across the United States about their values, beliefs, and behaviors. The MTF study, which began in 1975, is one of the few nationally representative data sets that tracks both political identity and fertility desires in young adults.
The sample used in this analysis included 67,557 participants surveyed between 1989 and 2019. Participants were asked how many children they wanted and to describe their political identity as either Republican, Democrat, or “Other,” which included independents or those without a preference. The study also gathered information on participants’ gender role attitudes, religiosity, and thoughts about childbearing to understand how these factors might explain partisan differences in fertility desires.
The results showed clear and consistent partisan differences. Across all time periods, Republicans wanted more children than Democrats. On average, Republicans desired 2.56 children, compared to 2.44 children among Democrats. The difference was small at first—just 0.06 children in the early years of the study—but it grew substantially over time. By the final period, 2014–2019, Republicans wanted 0.20 more children than Democrats. In particular, Republicans were more likely to want large families with four or more children, while Democrats increasingly expressed a preference for small families or even no children at all.
This partisan divide became more pronounced after 2003, a turning point in the study’s timeline. Before 2003, Republican and Democratic fertility desires were closer, with both groups fluctuating in their desires for larger or smaller families. But starting in the mid-2000s, Republicans began to consistently express a stronger preference for bigger families, while Democrats moved in the opposite direction, with an increasing number expressing a desire to be childless. The gap in fertility desires plateaued at high levels after 2003, suggesting that the divide between the two groups had become entrenched.
The researchers found that part of the reason for the partisan divide in fertility desires was linked to differences in religious beliefs and attitudes toward gender roles. Republicans were more likely to be religious and to support traditional gender roles, both of which have been shown in previous research to be associated with a desire for more children. Democrats, on the other hand, were less religious and more likely to support gender equality, which often correlates with smaller family sizes.
However, even after adjusting for these factors, political identity remained a strong and independent predictor of fertility desires. This suggests that party affiliation itself, beyond religious and gender views, is shaping how many children young adults want.
In addition to analyzing the number of children desired, the researchers also looked at the distribution of fertility desires. They found that the growing gap between Republicans and Democrats was driven by differences at the extremes of the fertility spectrum. After 2003, Republicans became significantly more likely to want very large families (four or more children), while Democrats became more likely to want no children at all.
For example, in the period from 2004 to 2008, 20% of young Republicans said they wanted four or more children, compared to just 15% of Democrats. By the period from 2014 to 2019, 7% of Democrats expressed a desire to remain childless, compared to 4% of Republicans.
The study’s findings point to several important trends. First, it shows that political identity is now a significant factor in fertility desires, on par with or even exceeding traditional factors like religiosity and gender role attitudes. Second, the results suggest that political affiliation has become more strongly linked to personal life decisions over time. In the 1980s and 1990s, the gap between Republican and Democratic fertility desires was relatively small and largely explained by differences in religious beliefs. But after 2003, political identity itself became a stronger predictor, independent of these other factors. This indicates that party affiliation may be influencing more aspects of people’s lives, including decisions about family size.
However, the researchers acknowledge that their study has some limitations. First, the data only includes 12th graders, which means the findings may not apply to older adults or young people who do not complete high school. Additionally, the study measures fertility desires, not actual fertility behavior. While fertility desires are a strong predictor of how many children people will eventually have, they do not always translate into reality. Other life events, such as career changes, financial difficulties, or health problems, may influence whether young people follow through on their early desires.
Finally, the researchers note that their analysis is correlational, not causal. While political identity is linked to fertility desires, the study does not prove that party affiliation causes people to want more or fewer children. Other unmeasured factors, such as views on climate change or abortion, may also play a role.
Future research could explore how these findings evolve as today’s young adults move into their childbearing years. It could also examine how other social identities, such as environmentalism or feminism, interact with political affiliation to shape fertility decisions. Understanding the connection between political identity and fertility desires is important not only for predicting future population trends but also for understanding how deeply political polarization affects everyday life.
The study, “Youth’s political identity and fertility desires,” was authored by Heather M. Rackin and Christina M. Gibson-Davis.