New York Times columnist Bret Stephens is once again stirring outrage—this time with a piece entitled “The Secrets of Jewish Genius” that cites a paper co-authored by an academic labeled an “extremist” eugenicist and celebrated by white supremacists.

Stephens’ op-ed on Ashkenazi Jews was denounced all over social media as an example of race science bunk.

“How is it that a people who never amounted even to one-third of 1 percent of the world’s population contributed so seminally to so many of its most pathbreaking ideas and innovations?” Stephens wrote.

He said that Jews “are, or tend to be, smart” and cited the 2005 paper “Natural History of Ashkenazi Intelligence” by Gregory Cochran, Jason Hardy, and Henry Harpending, which declares that Ashkenazi Jews have the highest average I.Q. of any ethnic group. Stephens’ take? “Ashkenazi Jews might have a marginal advantage over their gentile peers when it comes to thinking better. Where their advantage more often lies is in thinking different,” he wrote.

As Stephens began trending on Twitter and the New York Times’ tweet of his column was ratioed, the study he cited and its authors drew new scrutiny. Nieman Lab director Joshua Benton noted that the Times itself had published an op-ed last year by a Harvard geneticist, David Reich, in which he denounced Harpending’s work.

A 2005 Times article about the paper cited by Stephens quoted a Cornell University geneticist as saying Harpending and company “make pretty much all the classic mistakes in interpreting heritability,” though also quoted scientists with a less critical view.

The Southern Poverty Law Center has Harpending, who died in 2016, on its list of extremists and lists his ideology as “white nationalist.” 

“Harpending has given talks on these ideas at white supremacist conferences, and is widely celebrated among white supremacists on forums like Stormfront and the Vanguard News Network, who see a champion for their cause behind his academic rhetoric,” the center said.

Benton also pointed out in a Twitter thread that the lead author on the 2005 paper, Gregory Cochran, has a history of homophobia.

In the paper “An Evolutionary Look at Human Homosexuality,” Cochran wrote that homosexuality, from a biological perspective, is “surely a disease.” 

“So it’s a bug,” Cochran wrote. “Somehow, the brain has been damaged, but in a limited and focused way.”

The Times and Stephens did not respond to requests for comment.

The uproar over Stephens’ latest column follows the controversy that ensued in August after George Washington University professor David Karpf referred to him as a bedbug—prompting Stephens to complain to the school provost.

“I'm often amazed about the things supposedly decent people are prepared to say about other people—people they've never met—on Twitter. I think you've set a new standard,” Stephens wrote in the email, which Karpf later tweeted. “I would welcome the opportunity for you to come to my home, meet my wife and kids, talk to us for a few minutes, and then call me a ‘bedbug’ to my face. That would take some genuine courage and intellectual integrity on your part.”

Stephens deactivated his Twitter account in response, and wrote a column about Nazis and bedbugs just a few days later.