Summary: Does your success come from your parents’ bank account or their DNA? A new longitudinal twin study from the German TwinLife projec suggests the latter. The research tracked identical and fraternal twins from age 23 to 27 to see how intelligence and socioeconomic status (SES) develop.
The findings are striking: IQ is approximately 75% genetically predicted, and the link between a person’s IQ and their eventual income, education, and occupation is 69% to 98% explained by genetics. The study suggests that while a “silver spoon” upbringing matters, the genetic “hand” you are dealt is a far more powerful predictor of where you end up in life.
Key Facts
- The Twin Comparison: By comparing identical twins (100% shared genes) with fraternal twins (50% shared genes) raised in the same homes, researchers could isolate the impact of heredity versus environment.
- The 24-Hour Rule of IQ: IQ was tested at age 23, and SES (income/career) was measured at 27. The data showed that genes drive both intelligence and the ability to climb the socioeconomic ladder.
- Limited Parental Influence: The research suggests that while parents can provide opportunities, their ability to fundamentally change their child’s long-term socioeconomic success through “home life” alone is more limited than previously thought.
- Policy Paradox: The study raises difficult questions about social leveling policies. Kajonius notes that because genetic predispositions are so strong, it is difficult to create long-term change in SES through standard policy measures alone.
Source: Lund University
New twin research shows that innate IQ plays a major role in predicting your future socio-economic status.
The study, which follows twins during the crucial early adult years, reinforces the view that heredity and genes shape our life opportunities – and the people we become.
The saying “to be born with a silver spoon in one’s mouth” suggests that wealth and prosperity stem from the parents’ fortune. There is certainly some truth in that, but it is far from the whole truth.
“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.
The study is based on data from the German TwinLife project, which tracks twins over time to understand how genes and environment influence life. A total of around 880 individuals were included, half of whom were identical twins and half fraternal twins.
The pairs of twins grew up in the same family and therefore shared the same upbringing. Since identical twins share all their genes and fraternal twins share only about half, the researchers were able to establish how much of the differences between individuals is due to genes, and how much is due to environment.
The participants’ IQs were tested at the age of 23, and at the age of 27 their socio-economic status – education, occupation and income – was measured. This age range was chosen to capture a period when many had established themselves in adult life and begun their careers.
The results show that, statistically speaking, IQ is approximately 75 per cent genetically predicted and that the correlation between IQ and socioeconomic status are mostly explained by genetics, 69-98%.
“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.
Does that mean that policies aimed at levelling the playing field – such as those designed to help young people from families with little tradition of higher education achieve better grades – are a waste of time? Is a person’s future still predicted by their genes?
“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.”
It might sound as though everything is 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.”
Furthermore, Kajonius argues, the results could also be viewed with a degree of relief. Parents can stop blaming themselves. Admittedly, targeted interventions are valuable, but in the long run, the scope for influencing one’s children’s socio-economic success is quite limited.
And for young people, perhaps the findings might lead them to focus on what they enjoy most and are best at, rather than what maximises their socio-economic status.
Limitations of the study:
A limitation of this study is that it has not controlled for parents’ IQ and socio-economic status. A more general limitation of this type of model is that they often fail to account for the interaction between genes and environment – that is, genetic effects can manifest differently depending on upbringing.
This means that the high figure for genetic influence (75 per cent) may partly reflect such interaction effects, possibly by up to around 15 percentage points.
Key Questions Answered:
A: Hard work always matters, but this study suggests that our capacity for certain types of work and our drive are heavily influenced by our genetic blueprint. Genes set the “range” of what we can achieve; hard work determines where within that range we land.
A: Not at all, but they might be able to breathe a sigh of relief. Kajonius suggests these findings should reduce parental guilt. Since a child’s path is so strongly influenced by their own innate traits, parents can focus more on supporting what their child is naturally good at rather than trying to “mold” them into a specific socioeconomic bracket.
A: The researcher describes the results as a “description of reality.” While targeted interventions are valuable for providing immediate opportunities, the study suggests we must understand that people are born with different genetic predispositions. Policies may need to be redesigned to support different types of talent rather than assuming everyone can reach the same SES outcome with the same environment.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this IQ and genetics research news
Author: Lotte Billing
Source: Lund University
Contact: Lotte Billing – Lund University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Longitudinal associations betweencognitive ability and socioeconomicstatus are partially genetic innature” by Petri Kajonius. Scientific Reports
DOI:10.1038/s41598-026-37786-3
Abstract
Longitudinal associations betweencognitive ability and socioeconomicstatus are partially genetic innature
Individual’s future socioeconomic status (SES) has been reported to be robustly predicted by cognitive ability (IQ). However, research on the genetic and environmental underpinnings of this association in emerging adults remains limited.
Utilizing the German TwinLife panel data, the present study examined how IQ at early adulthood at age 23 is associated with SES at age 27 (NMZ = 228 and NDZ−SAME SEX = 212), through 2 measures on educational attainment and 2 on occupational status. Cholesky decomposition models reported the heritability of IQ at approximately 75%, and heritability on all SES outcomes.
Genetic factors further explained most of the IQ–SES association (69–98%), and genetic correlations between IQ and SES exceeded environmental correlations.
These findings seem to underscore the importance of researchers and policymakers to also considering genetic factors when examining the life outcomes of young adults.
