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A study published in Evolutionary Psychological Science found that people who endorsed more conservative social attitudes tended to report having more children across a large international sample, suggesting that these attitudes may be linked to contemporary reproductive patterns.
Social attitudes are broad orientations toward social life, including views about religion, politics, hierarchy, gender roles, sexuality, and authority. In this article, “conservatism” is used in a broad sense to refer to a shared tendency across attitudes such as right-wing ideology, religiousness, lower support for gender equality, and preference for religiousness in romantic partners.
The study builds on prior research showing that these attitudes often correlate with one another and that many social attitudes show some degree of heritability. That heritability is part of what makes them interesting from an evolutionary standpoint, particularly if they’re also tied to how many children people have.
Janko Međedović set out to investigate exactly that. His motivation came from a gap in evolutionary behavioral ecology; researchers have extensively studied how personality, cognition, and religiousness relate to fertility, but social attitudes more broadly have largely been left out of that conversation. Given that conservative worldviews tend to emphasize family formation, traditional gender roles, religious commitment, and pronatalist values, Međedović wanted to test whether people who hold these attitudes actually report having more biological children.
The study used a publicly available dataset originally collected for research on romantic love and mate preferences. The full dataset included 117,293 participants from 175 countries, with data collected mostly online in 2021 (Algeria and Morocco used paper-and-pencil surveys; Russia used Toloka; Iran used Google Forms). After removing participants with missing data on key variables and excluding countries with fewer than 100 respondents, the final analytic sample included 78,754 participants from 72 countries. About two-thirds of the sample were women.
Participants answered questions about political ideology (a single item, far-left to far-right), support for gender equality (a three-item scale, where higher scores meant stronger support), religiousness (an 11-point self-report item), preference for religiousness in an ideal romantic partner (a parallel 11-point item), and number of biological children. They also reported their gender, age, education level, and social class, variables that can shape both attitudes and family formation in important ways.
Međedović found that conservative social attitudes were consistently linked with higher fertility. Participants who reported stronger right-wing ideology, stronger religiousness, stronger preference for religiousness in a romantic partner, and lower support for gender equality tended to report having more children. The associations were generally small—age was by far the strongest predictor of how many children someone had—but they were consistent enough to show up reliably in a sample of nearly 80,000 people spread across 72 countries.
The size of the relationship between conservative attitudes and fertility also varied considerably across countries, and in a small number of cases it even flipped direction. This suggests the attitude-fertility link is not a fixed universal mechanism, and that national and cultural context shapes it in meaningful ways.
Several more specific patterns also emerged. Right-wing ideology and lower support for gender equality were more strongly associated with fertility among women than men, suggesting that conservative attitudes may be especially tied to women’s reproductive outcomes in this dataset. Self-reported religiousness was strongly associated with preferring a religious romantic partner, and the interaction between these variables showed that people low in religiousness who also preferred nonreligious partners had especially low fertility. Education further qualified the findings: right-wing ideology predicted higher fertility among less educated participants, but not among highly educated participants.
The author also found small quadratic effects, but described these as slight departures from linear associations rather than strong evidence of a clearly nonlinear pattern.
Međedović notes several important limitations. Women and more educated participants were likely overrepresented, and many participants were still young enough that they may not have completed their reproductive years (average age for men = 31.5 years, women = 29.5 years). The cross-sectional design also means the study cannot establish that conservative attitudes cause higher fertility or that they are definitely evolving through selection. As well, several attitudes were measured with only one item, which also limits measurement reliability.
Still, the findings make a reasonable case that social attitudes deserve more attention in research on fertility differences, while also raising the possibility that attitudes could be relevant to contemporary human behavioral evolution.
The research “Conservative Social Attitudes are Linked with Fertility: A Potential for Positive Directional Selection” was authored by Janko Međedović.
