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Being tall is associated with higher income for men and being overweight is associated with lower income for women. A new study shows that height and weight may have a direct cause-and-effect relationship with pay.

The study used Mendelian randomization — a genetic technique that helps clarify the causal relationship between human characteristics — to show that genetically determined height and weight can directly affect worldly success.

British researchers studied 119,669 men and women who either had or did not have various genetic variants known to influence height and B.M.I.

The study, in BMJ, found that for each two and a half inches of genetically determined extra height, a man was 12 percent more likely to work in a high-status job and earned an average $1,611 more a year. In women, a 4.6-point increase in B.M.I. resulted in $4,200 less in annual income. These differences between the sexes strengthen the conclusion that the effect has a genetic basis, independent of environment.

That taller men and thinner women are more successful has been shown in several observational studies, and environmental factors are certainly involved.

“But your environment, your lifestyle, can’t change your genes,” said the senior author, Timothy M. Frayling, a professor of human genetics at the University of Exeter. “The data shows that there is a causal effect from being genetically a bit shorter or fatter that leads you to being worse off in life. Previously we didn’t know that.”