Why do some kids do so much better in school than others? The conventional wisdom is that a lot of it comes down to privilege. Kids from wealthier families benefit from access to better schools, private lessons and greater parental investment. Kids from poorer families don’t have those benefits. To level the playing field, society should try to close the gap in whatever way it can.

But what if their environment doesn’t matter all that much? What if the biggest impact parents have on their children is their genetics?

Increasingly, research shows just that.

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These findings are coming dizzyingly fast. Genetics research has been revolutionized by cheap genomic scanning, which allows the human genome to be analyzed in stunning detail at very low cost. Researchers can now compare the genetic results of tens of thousands of individuals and see how they match up to educational attainment, wealth, and socioeconomic status.

A new study came out this week and it’s a blockbuster. Daniel Belsky of the Duke University School of Medicine and his research team studied the life trajectories of 20,000 people in the United States, Britain and New Zealand – a huge sample size. What they found is that certain education-linked gene variants “can modestly predict people’s educational and economic success.” They refer to the sum total of these gene variants as a “polygenic score.” Put simply, people with high scores do better.

What are education-linked gene variants? People who have more of them learn to read faster. They do better on intelligence tests. They have more education. They marry other educated people. As research scientist Stuart Ritchie explained in Business Insider, “The idea is that the education-linked genes make people smarter, harder-working, and more socially successful – traits that help you lead a more ‘successful’ life.”

The Belsky study also found, not surprisingly, that success tends to be hereditary. Successful parents tend to have successful children. But why is that? Is it the upbringing they give the kids? Or is some biological mechanism at work? To answer this question, the study examined social mobility to find out which people wound up doing better or worse than their parents. What they found was that people with more of the “success” genes are also more upwardly mobile. They tend to surpass their parents in wealth and social status. In other words, although they no doubt benefit from a favourable environment, they are also “encoded” for success. People who have higher polygenic scores than their siblings – even though raised in the same environment – also go farther in life than their siblings do. And people with higher scores who are born into poorer families also do well. As Mr. Belsky told the Harvard Business Review, “Higher scores predicted success no matter what kind of conditions a child grew up in.”

How strong are these findings? According to the researchers, the underlying genetic scores had about the same correlation with actual educational attainment as standardized testing does with success in schooling. Not long from now, you won’t have to wait to find out if your kid is a brainiac. You can just give her a cheek swab the day she’s born.

One study on its own proves nothing. But the evidence is mounting that the best predictor of your life’s outcome (assuming you grow up in the affluent West) isn’t your upbringing. It’s your genetic makeup.

A lot of people are deeply resistant to the new emphasis on genetics. After all, it smacks of biological determinism. It is also deeply threatening to the way we think about the world. A great deal of social policy (and almost all educational policy) is founded on the idea that properly designed social interventions can reduce inequality by levelling the playing field between the haves and have-nots. Isn’t the implication of biological determinism that we should just throw in the towel?

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Mr. Belsky doesn’t think so. He thinks a better understanding of genetics might help us devise policy interventions that work better than the current ones. Other people think that a better understanding of genetics might allow us to devise education plans that are individually tailored to maximize the potential of each kid. In any event, Mr. Belsky points out that we’d better start discussing these issues, because the genetics revolution isn’t going to go away. As he told HBR, researchers are now investigating genetic influences in everything from risk taking and entrepreneurship to reproductive behaviour and social relationships.

And if you have a bunch of the “success” genes, don’t be too smug. You may feel like you earned them. But you’re just lucky.