Some rejected the tests entirely, saying that an individual’s knowledge about his or her own genealogy is better than whatever a genetic test can reveal. “They will talk about the mirror test,” said Panofsky, who is a sociologist of science at UCLA’s Institute for Society and Genetics. “They will say things like, ‘If you see a Jew in the mirror looking back at you, that’s a problem; if you don’t, you’re fine.’” Others, he said, responded to unwanted genetic results by saying that those kinds of tests don’t matter if you are truly committed to being a white nationalist. Yet others tried to discredit the genetic tests as a Jewish conspiracy “that is trying to confuse true white Americans about their ancestry,” Panofsky said.

But some took a more scientific angle in their critiques, calling into doubt the method by which these companies determine ancestry — specifically how companies pick those people whose genetic material will be considered the reference for a particular geographical group.