But “these genes are not deterministic,” adds Benjamin. There’s a common myth that our traits can be divided into a fixed portion that’s “in our genes” and pre-destined from conception, and a flexible portion that depends on the environment and is under our control. That’s wrong. Nature and nurture are not opposed; they go hand in hand. The environment sets the stage upon which genes act out their roles.

For example, the team found that their 74 variants has a much stronger effect on educational attainment among Swedes born in the 1930s than those born in the late 1950s. Between those years, Sweden introduced reforms that extended mandatory schooling by two years, and improved access to schools and universities. The weakening influence of genetic factors over the same timeframe “is consistent with the possibility that the reforms equalized educational outcomes,” says Benjamin.

So, educational success is not “in the genes”, nor can you “blame your genes” if you flunk out. That’s especially true because each of the team’s 74 variants had a tiny effect, equivalent to just 3 to 9 weeks of extra schooling. And collectively, they explained just 3 percent of the differences in education levels across the whole population. “For comparison, professional weather forecasts correctly predict about 95 percent of the variation in day-to-day temperatures,” the team writes in their FAQ. “Weather forecasters are vastly more accurate forecasters than social science geneticists will ever be.”

For that reason, you can’t reliably use these 74 variants to predict how long a child will stay in education, or to stratify children according to how much support they’ll need. “It’s not a smart way to use the score,” says Benjamin. The same applies to any unwarranted talk of eugenics—of selecting for embryos with particular genes, or even using gene-editing technologies to alter said genes. These would be dumb ways of ensuring smarts; if you’re really that concerned, you’re better off just dating someone clever.

But if it took so much effort to find genes that have such small effects, and that can’t usefully predict anything, what was the point of even looking? Why did the team bother?

Partly, Benjamin says, to draw a line in the sand. Many earlier studies had searched for genetic variants linked to intelligence or academic performance, but their results were often misleading and irreproducible. That’s because they were absurdly small. With anywhere from 50 to 2,000 volunteers, they had nowhere near the statistical oomph they needed to reliably detect the variants they were looking for.

Medical geneticists had confronted the same problems of weak methods and phantasmal results. Their solution was to join forces and pool the data from many smaller studies—which is exactly what Benjamin, Cesarini, and Koellinger did. In 2011, they founded the Social Science Genetic Association Consortium (SSGAC). For their first study, published in 2013, they looked at 101,000 people and found three genetic variants linked to educational level. Now, with almost three times as many volunteers from 64 separate samples, they have found another 71 variants. They even cross-checked their list using a set of 113, 000 more recruits from a separate UK-based study.