A new study published in Social Science Research provides evidence that the way genetics influence a person’s educational success depends heavily on their family background, their gender, and the school system in their country. By comparing data across four European nations, scientists found that early educational tracking tends to increase the impact of family background while reducing the role of genetics in a student’s academic journey.
Scientific interest often centers on how a family’s socioeconomic status interacts with a child’s genetic traits to shape their future. Socioeconomic status refers to a family’s social and economic standing, frequently measured by the parents’ education and income levels. Inherited traits, such as cognitive abilities and behavioral skills, play a natural role in how well people do in school. However, a person’s living environment might either limit or encourage the expression of those inherited traits.
Hannu Lehti, an academy research fellow at the Invest Flagship Center at the University of Turku, led the project to better understand how these two forces interact. “I have always been interested in combining biology and social sciences, because we humans are not only social creatures, our behavior also depends on biological factors,” Lehti said. “Behavior is not possible without biology, but the social environment also shapes and modifies it.”
Some past research suggests that children from highly educated families have more resources, which helps them reach their full genetic potential in the classroom. This is known as an enhancement effect. In this scenario, supportive environments act as a fertilizer for natural ability, allowing genetic differences to shine through.
Other studies suggest an opposite pattern, known as a compensation effect. In this situation, wealthy or highly educated families use their extra resources to help a child overcome genetic disadvantages, such as learning difficulties or behavioral challenges. This extra help means the family environment ends up playing a larger role in the child’s academic success, smoothing over any natural deficits.
To understand these conflicting patterns, the authors of the current study wanted to look beyond the immediate family. “My PhD focused on intergenerational education and socioeconomic mobility using sibling designs, but I could not account for genetic factors because I lacked access to twin registers,” Lehti explained. “The natural next step was to examine the relative contributions of genes and environment. I applied for funding to pursue this, received a four-year grant from the Research Council of Finland, and this paper was one of those I planned in the application.”
The scientists suspected that larger social forces, like gender expectations and national school systems, also filter how genetic traits express themselves. “In the study, we wanted to analyze whether institutional differences between countries influence genetic and environmental effects on educational attainment between families and sexes,” Lehti said.
“We used large twin registers from Finland, Norway, Germany, and the Netherlands, analyzing gene-by-environment interactions by parental education and child gender using non-parametric gene-environment interaction models,” Lehti added. Non-parametric models are flexible statistical tools that allow researchers to look for complex patterns in the data without making strict assumptions about the shape of the relationship beforehand.
To test these ideas, the scientists analyzed data from identical and fraternal twins, as well as regular siblings, across the four nations. Identical twins share all of their DNA, while fraternal twins and regular siblings share about half. By comparing how similar the educational outcomes are among these different types of siblings, scientists can estimate how much of a trait is due to genetics, how much is due to the shared family environment, and how much comes from unique personal experiences.
The authors gathered extensive registry and survey data for people born mostly between 1980 and 1998. The total sample included exactly 116,772 individuals from Finland, 271,902 individuals from the Netherlands, 3,958 individuals from Norway, and 3,064 individuals from Germany. The scientists measured educational attainment by calculating the total years of schooling each person completed by the time they reached their late twenties or older. They also categorized the parents’ highest level of education as either low or high.
The data revealed that the influence of genetics on educational attainment varies depending on the country. Genetic factors had the strongest influence on education in Finland, followed by the Netherlands, Norway, and Germany. At the same time, the shared family environment had the strongest impact in Germany and the weakest in Finland.
“We found no differences between sexes, but there were differences between countries, suggesting that educational systems influence heritability, a gene-environment interaction at the institutional level,” Lehti told PsyPost. The authors indicate that these national differences align with how each country structures its schools.
Germany and the Netherlands sort students into different academic tracks around age ten or twelve. In such systems, parents often have to use their own resources to help their children navigate early academic transitions. “Countries with very early educational tracking show smaller genetic effects and larger shared environmental effects, meaning twins are more similar to each other in these countries, such as Germany,” Lehti said. Finland and Norway delay this academic tracking until age sixteen, which appears to allow individual genetic abilities to play a larger role in a student’s final educational attainment.
The researchers also looked for gender differences in the overall genetic effects. They originally anticipated that men might show smaller genetic influences than women, especially in countries with early school tracking. Yet, they found no significant gender differences in the overall magnitude of genetic or environmental effects on education in any of the four countries.
“A surprising finding was that there were no sex differences in genetic effects within countries, even though men’s educational attainment has consistently been shown to be lower than women’s,” Lehti said. This suggests that men and women in these modern generations have an equal baseline of genetic influence when it comes to educational success.
“It has been shown that men are also more sensitive to different social environments, such as family background, but we did not find significant differences,” Lehti explained. “I expected that shared environmental effects would be larger for men in Germany, where educational decisions are made earlier than in other countries.”
When the researchers looked at how parental education specifically changed these genetic effects, the results became more complicated. For women in Finland, Norway, and Germany, they observed a compensation effect. This means that genetic influences were weaker, and environmental influences were stronger, for women who grew up in highly educated families. Highly educated families appeared to use their resources to buffer their daughters against any natural academic disadvantages.
For men, the patterns varied much more depending on the country. A compensation effect for men only appeared in Finland. In Germany, the data showed that the shared family environment had a particularly strong impact on men from families with low parental education. This provides evidence that early school tracking might be especially challenging for boys from less educated backgrounds. For these boys, their educational outcomes become heavily dependent on their family’s situation rather than their natural academic abilities.
It is important to note that a strong genetic influence does not mean biology is destiny. “Genes are not deterministic; social structures such as educational systems influence heritability,” Lehti noted. “Thus, gene-environment interplay matters. There are no single genes for education; in fact, there are no ‘education genes.’ The genetic effects on education operate through indirect pathways via other traits, such as cognitive and noncognitive abilities.”
The study, like all research, includes some caveats. The sample sizes for Norway and Germany were much smaller than those for Finland and the Netherlands. Smaller samples naturally increase the mathematical uncertainty of the statistical estimates. It is possible that some of the differences between the countries are influenced by the specific types of data collected rather than just the national school systems.
“We used twin models, which rely on a number of assumptions,” Lehti said. “The most important is the equal environments assumption, that identical and fraternal twins are treated similarly by their environment. However, we could not test all the assumptions with our data, but previous studies have pointed out that the assumptions are rather robust.”
Additionally, the registries in Finland and the Netherlands did not contain exact information on whether twins were identical or fraternal. The scientists had to estimate this by comparing same-sex siblings to opposite-sex siblings. A future approach could help address these estimation issues by directly examining a person’s DNA.
“I would like to study the traits that mediate genetic effects on education, since it is clear that there is no single gene for educational attainment,” Lehti said. “Also, considering genetics on the molecular level using the polygenic score method, I plan to move in that direction in the future.” Polygenic scores involve analyzing thousands of small genetic variations across a person’s DNA to estimate their biological likelihood for a specific trait, offering a more direct way to study these complex interactions.
The study, “The role of gender in gene by family SES interactions – A twin study across four European countries,” was authored by Hannu Lehti, Kim Stienstra, Tina Baier, and Torkild H. Lyngstad.