Genetics significantly shapes IQ and future socioeconomic status, with environmental influence playing a smaller role than often assumed.
New research on twins suggests that innate intelligence plays a major role in shaping a person’s future socioeconomic status. By tracking twins during early adulthood, the study strengthens the idea that genetics influence both life opportunities and personal development.
The phrase “to be born with a silver spoon in one’s mouth” implies that success mainly comes from family wealth. While family background does matter, it does not explain everything.
“The so-called ‘silver spoon’ isn’t as big as you might think. Your home life also depends on your genes,” says personality psychologist Petri Kajonius, who recently published a study in Scientific Reports.
Twin Study Methodology and Shared Environment
The research draws on data from the German TwinLife project, which follows twins over time to examine how genetics and environment shape life outcomes. The study included about 880 participants, split evenly between identical twins and fraternal twins.
Because the twins were raised in the same household, they shared similar environments growing up. However, identical twins share all of their genes, while fraternal twins share about half. This difference allowed researchers to estimate how much variation between individuals is linked to genetics versus environmental factors.
Participants took IQ tests at age 23. At age 27, researchers assessed their socioeconomic status, including education, occupation, and income. These ages were selected to capture a stage when many people have begun establishing careers. The findings indicate that about 75 percent of IQ is genetically influenced. In addition, the link between IQ and socioeconomic status is largely explained by genetics, ranging from 69 to 98 percent.
Strong Genetic Link Between IQ and Socioeconomic Status
“We knew this before, but this study shows even more clearly that we are driven by our genes and become who we are largely because of them,” says Petri Kajonius.
These results raise questions about policies designed to level the playing field, such as programs that support students from families without a strong history of higher education. Do such efforts have limited long-term impact if genetic differences play a large role?
“The study shows that we are born with different genetic predispositions and that it is difficult to bring about long-term change in this regard through policy measures.”
Rethinking Determinism, Responsibility, and Study Limitations
At first glance, the findings may suggest that life outcomes are largely predetermined.
“As a researcher, my job is to describe reality as accurately as possible. If we want to change society, we must, of course, understand the underlying assumptions.”
Kajonius also notes that the results may offer some reassurance. Parents may feel less pressure to blame themselves for their children’s outcomes. While targeted support can still help, its long-term influence on socioeconomic success appears limited. For young people, the findings may encourage focusing on personal interests and strengths rather than strictly aiming for a higher status.
The study does have limitations. It did not account for parents’ IQ or socioeconomic status. More broadly, this type of analysis often struggles to capture how genes and environment interact. Genetic effects can vary depending on upbringing, meaning the estimated genetic influence of 75 percent may partly reflect these interactions, potentially by up to about 15 percentage points.
Reference: “Longitudinal associations between cognitive ability and socioeconomic status are partially genetic in nature” by Petri J. Kajonius, 2 February 2026, Scientific Reports.
DOI: 10.1038/s41598-026-37786-3
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5 Comments
If the only thing in life were money.
I can’t believe they just left these factors out, but success in life is also determined by likability (personality, attractiveness) and health. Health is a huge factor. Health and likability are both determined by genetics and it doesn’t look like the study accounted for that since the twins also shared those genes, besides the genes for high IQ.
So lead has lowered the IQ of USAians. My father surmised that in around 1964 to explain why the USA was such a violent place. Gas-guzzling cars, lead tetraethyl in petrol and vast rose of cars driving everywhere.
I feel that the limitation of the study mentioned by the author explains many loopholes in the study. The IQ test, while an interesting phenomenon, is not the answer to understanding the limitations that the test provides. And, a test at 25 providing results at 27, to me, seems too short to draw such a conclusion.
IQ test only prove one thing, how good you are at IQ tests.