Demographic differences in fertility linked to generational shifts in the political landscape

Could demographics be the key to understanding political change? A recent study published in Biodemography and Social Biology has found that conservatives in Europe tend to have more children and grandchildren than liberals, a trend that is shifting the balance of political attitudes over time. These findings suggest that reproductive behavior might play an unexpected role in shaping the political landscape.

Political attitudes are known to be relatively stable over the lifespan and are shaped by both social and genetic factors. These attitudes often play a role in behaviors such as marriage, family formation, and parenting. Previous research has highlighted that conservative individuals tend to prioritize traditional family structures, which might contribute to higher fertility rates. In contrast, liberal individuals often emphasize personal autonomy and individualism, which could lead to lower fertility.

Researchers Martin Fieder and Susanne Huber were interested in exploring whether these fertility differences could result in a demographic shift in the prevalence of political attitudes. If conservatives consistently have more children than liberals, and political orientations are passed down socially and genetically, it could lead to a gradual increase in conservative views across generations. This could, in turn, affect the political landscape and the balance of ideologies in a society over the long term.

The new study builds on the researchers’ prior work, which identified a positive association between conservative political orientation and higher fertility in Western societies. However, the researchers wanted to go beyond simply documenting this pattern. They sought to explore its potential consequences for political systems and societal attitudes.

“As evolutionary anthropologists, we are interested in the evolution of our political attitudes. Having found that there is only a reproductive advantage for the right in Western societies, we wanted to demonstrate the potential consequences of this right-wing advantage for our political system,” said Fieder, an associate professor of evolutionary demography at the University of Vienna and author of Not So Weird After All: The Changing Relationship Between Status and Fertility.

The researchers used two large datasets to examine the relationship between political attitudes and fertility: the Survey of Health, Ageing, and Retirement in Europe (SHARE) and the European Gender and Generation Survey (GSS). These datasets included information from multiple European countries, with SHARE also incorporating data from Israel. SHARE provided data on political orientation and family size across three generations, while GSS offered additional insights into attitudes toward family and sexuality.

In the SHARE data, participants aged 45 and older, totaling over 66,000 individuals, were asked to self-report their political orientation on an 11-point scale ranging from extreme left to extreme right. This scale was later simplified into broader categories—left, middle, and right—to facilitate analysis. The researchers calculated the average number of children and grandchildren for each participant, comparing these figures across political orientations. They also assessed generational changes by examining the proportion of conservative versus liberal individuals among participants, their children, and their grandchildren.

The GSS data included responses from over 120,000 individuals and focused on attitudes toward family and reproduction. Participants were asked whether they agreed or disagreed with statements such as “Homosexual couples should have the same rights as heterosexual couples” and “A woman must have children to feel fulfilled.” These attitudes were categorized as left, middle, or right, and were analyzed alongside participants’ family sizes.

The researchers found a consistent relationship between political conservatism and higher fertility. In most European countries included in the SHARE data, individuals with more conservative attitudes had more children and grandchildren than their liberal counterparts. For example, participants who identified as right-leaning on the political spectrum consistently reported larger family sizes. This pattern was particularly evident among individuals with the most conservative views, suggesting a strong link between traditional values and reproductive behavior.

Additionally, the researchers observed a generational shift in the proportion of conservative individuals. In most countries, the percentage of individuals identifying as conservative increased from grandparents (the first generation) to grandchildren (the third generation). This trend indicates that demographic factors, such as higher fertility among conservatives, may contribute to a gradual increase in the prevalence of conservative attitudes over time.

The GSS data supported these findings, showing that individuals with conservative attitudes toward family and reproduction tended to have larger families. For instance, those who believed that women must have children to feel fulfilled or who opposed equal rights for homosexual couples were more likely to have more children compared to those with liberal attitudes. This pattern was consistent across many of the countries included in the analysis.

The findings indicate that “demographics and the different fertility rates of left-wing versus right-wing individuals are important to understanding long-term political trends, and that the rise of right-wing parties/individuals we are currently seeing is also a consequence of demographics,” Fieder told PsyPost.

In some nations, such as Germany and France, the shift toward conservatism was particularly pronounced, with the proportion of conservative individuals in the younger generations increasing by more than 8 to 11 percentage points compared to the older generations.

Fieder said he was surprised by “the magnitude and strength of the demographic trends.”

Despite these overall trends, there were some exceptions. For example, in Israel, left-leaning individuals reported higher fertility rates than their right-leaning counterparts, an anomaly the researchers attributed to cultural and religious factors unique to that region. Additionally, some countries, such as Sweden, showed weaker or inconsistent associations between political orientation and family size.

Interestingly, the data also indicated that the fertility advantage among conservatives is relatively recent. In the grandparent generation, left-leaning individuals in many countries had larger sibling groups than conservatives. This reversal suggests that changes in societal norms, such as increased access to contraception and shifts in attitudes toward marriage and family, may have amplified the fertility differences associated with political orientation over time.

The researchers used statistical models that controlled for variables like age, education, and country of residence. This approach allowed them to isolate the effect of political attitudes on family size while accounting for other influencing factors. But the study, like all research, has limitations.

For instance, the SHARE dataset does not distinguish between biological and non-biological children, which could affect the accuracy of fertility estimates. Furthermore, while the findings suggest a recent reproductive advantage for conservatives, the underlying causes of this shift remain speculative and require further investigation.

The long-term goal for this line of research is to obtain “a better understanding of the evolution of our political attitudes and why they divide us so much,” Fieder said.

The study, “Demography leads to more conservative European societies,” was published November 24, 2024.