Although the Holocaust was propelled by charges that Jews were genetically inferior to Aryans, a new study in the Journal of Biosocial Science published online in June supports the opposite notion: Ashkenazi Jews may be genetically predisposed to higher intelligence.

In the past, powerful figures, including Adolf Hitler, manipulated pseudoscientific ideas to fuel prejudice. But legitimate biological techniques now allow researchers to identify the functions of specific genes. Gregory Cochran, the infamous independent evolutionary biologist who in 1992 proposed that homosexuality is caused by an infectious disease, has teamed up with anthropologists Henry Harpending and Jason Hardy of the University of Utah. They claim that Ashkenazi Jews—an ethnic group that includes physicist Albert Einstein, psychoanalyst Sigmund Freud and composer Gustav Mahler—are more intelligent because of genetic mutation.

“People would like every group to be exactly the same,” Cochran says, “but they’re not.” The study claims that intelligence evolved in this genetically isolated population because, historically, Ashkenazim had cognitively demanding occupations such as financiers and merchants. Prowess in these fields provided prosperity and, so the theory goes, more success in reproduction. Thus, the “IQ gene” passed down through generations.

At the same time, the researchers noted that genetic diseases common to the group, including Tay-Sachs and Gaucher's, result from increased levels of a chemical that also promotes neuronal growth. After assessing the genetic clustering of mutant genes and correlating these with IQ scores, the researchers contend that the genetic diseases are linked to a propensity for greater intelligence. The survival edge conferred by higher IQs in the group makes up for individual penalties from the diseases.

Most scientists insist that cultural factors play critical roles in the development of a person's intelligence. But Cochran is convinced that across generations, a person's environment is insignificant compared with strong biological factors. “As genetics marches on, there are a lot of things people think are cultural, and they’re turning out not to be,” he says.

The sordid history of mixing genetics, ethnicity and intellect guarantees a spotlight on this work. But only time and rigorous research will tell if genes are the most important factor in conferring smarts.