smartboy10 / Getty

Genetic-ancestry tests are having a moment. Look no further than Spotify: On Thursday, the music-streaming service—as in, the service used to fill tedious workdays and DJ parties—launched a collaboration with AncestryDNA. The partnership creates custom playlists for users based on DNA results they input: Oumou Sangaré for Mali, for example, and Ed Sheeran for England.

And last May, after the U.S. men’s soccer team had embarrassingly missed the World Cup, 23andMe also saw a marketing opportunity. “What is a soccer nut to do?” the company asked in a blog post. “Here’s an idea—why not pick a team based on your genetic ancestry?”

There’s an Ancestry ad where a man trades his lederhosen for a kilt. And another where a woman traces her ancestry to the matriarchal Akan people of Ghana to conclude, “When I found you in my DNA, I learned where my strength comes from.” And yet another where a man bonds with his Irish neighbor after finding out his own DNA is 15 percent Irish.

DNA, these marketing campaigns imply, reveals something essential about you. And it’s working. Thanks to television-ad blitzes and frequent holiday sales, genetic-ancestry tests have soared in popularity in the past two years. More than 15 million people have now traded their spit for insights into their family history.

If this were simply about wearing kilts or liking Ed Sheeran, these ads could be dismissed as, well, ads. They’re just trying to sell stuff, shrug. But marketing campaigns for genetic-ancestry tests also tap into the idea that DNA is deterministic, that genetic differences are meaningful. They trade in the prestige of genomic science, making DNA out to be far more important in our cultural identities than it is, in order to sell more stuff.

First, the accuracy of these tests is unproven (as detailed here and here). But putting that aside, consider simply what it means to get a surprise result of, say, 15 percent German. If you speak no German, celebrate no German traditions, have never cooked German food, and know no Germans, what connection is there, really? Cultural identity is the sum total of all of these experiences. DNA alone does not supersede it.

Listening to 99 Luftballons or rooting for Germany in the World Cup is fairly trivial as these things go. But this wave of marketing campaigns encourages a way of thinking—that you can pick and choose which fractional parts of genetic identity to highlight when it makes for good cocktail-party conversation.

At a recent genetic-genealogy meeting I attended, an audience member asked how to convince people to upload their DNA results to more genealogy sites. “Tell them they’ll find they’re Native American and they’ll all go,” another person in the audience joked. The whole room laughed in recognition. Native American ancestry is an enduring fascination among Americans, and genetic-ancestry tests tap into an idea that something interesting, something unknown, might be buried in the past.

That’s the annoying version of conflating DNA and cultural identity. The even more insidious version is using genetic ancestry to game programs set up to address past injustices. As a demonstration of how that could be done, a man in Washington State cited a DNA test as evidence of his African (4 percent) and Native American (6 percent) ancestry.

When I previously spoke to Kim TallBear, a professor at the University of Alberta, about the case, she said it showed a grave misunderstanding of Native American identity. “It might be all these people have Native American ancestry,” she said. “My question is: Who cares?” Native American tribes usually require identifying relatives for membership. “If there’s a particular ancestor that is close enough you can find living family, then you can do that,” TallBear added. “If there’s nobody for you to find and no tribal community that’s going to claim you, it doesn’t really mean anything.” Nevertheless, she says, as genetic-ancestry tests have become popular, people have been showing up at tribal-enrollment offices with their results.

The most charged criticism against genetic-ancestry tests is that they emphasize people’s genetic differences, ultimately reifying race as a meaningful category when it is in fact a social construct. A 2014 study found that when people read a newspaper article about genetic-ancestry tests, their beliefs in racial differences increased. And white nationalists have taken to DNA ancestry tests to prove their European heritage.

DNA-testing companies are careful not to use racial categories in their tests, instead reporting breakdowns of specific regions around the world. And they say that their tests are meant to bring people together by highlighting shared ancestry and challenging the idea that people are “pure.” I don’t doubt that DNA tests have sparked meaningful explorations of family history for some people and filled in the blanks for others whose histories were lost to slavery and colonialism. I do doubt that a DNA test will solve racism.

In November 2016, I got an email from an AncestryDNA publicist with the subject, “Post-election spike in DNA interest.” The publicist wanted to share some numbers: Ancestry’s DNA-kit sales jumped 33 percent compared to the week before the election. She attributed this to a viral video called The DNA Journey, where people are first seen talking about how proud they are of their heritage and dumping on others (“I have a side of me that hates Turkish people”). Then they take a DNA test and find out that they, in fact, have mixed ancestry.

In the divisive days after the election, the publicist said readers were hungry for this message. “PLEASE DO THIS! Let’s stop spreading hate and start seeing that we are all one! I just ordered my kit! We all bleed the same color!” is how she characterized viewers’ reactions. “This should be compulsory,” one woman exclaims in the video. “There would be no such thing as, like, extremism in the world.”

It’s a nice message. But it elides history. Mixed ancestry does not necessarily mean a harmonious coexistence, past or future. African Americans have, on average, 24 percent European ancestry. To take a genetic-ancestry test is to confront a legacy of rape and slavery—perhaps to even recognize one’s own existence as the direct result of it. There is a way to use genetics and genealogy to uncover injustices and properly account for them. The 23andMe-sponsored podcast Spit, for instance, has featured some nuanced conversations about race. But it’s not through feel-good ads that paper over the past.

At the end of The DNA Journey (36 million views on Facebook and counting), participants are offered a trip around the world to visit the places revealed in the DNA test. The video was, of course, an advertisement: a collaboration between AncestryDNA and Momondo, a travel website.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.