How to Argue With a Racist

By Adam Rutherford

10 min read

Why does it matter? Because the racists are already using the genetics — and getting it completely backwards.

The standard liberal response to racist pseudoscience — "race is just a social construct" — is correct, and it isn't enough. Racists have moved on to genetics, to misread ancestry tests and cherry-picked genetic association studies. If you only have the dismissal and not the data, you'll lose that argument.

Adam Rutherford is a geneticist with a personal stake in the argument. What follows is the actual science: why skin color is a catastrophically poor proxy for anything, why every European alive descends from every tenth-century European ruler and peasant alike, why claims about Black athleticism and Jewish intelligence collapse under the molecular evidence that supposedly supports them. The weapon isn't the dismissal. It's the data.

The Racists Are Quoting the Same Field That Already Refutes Them

In 2018, neo-Nazis across America began filming themselves drinking cow's milk (shirtless, in deliberate display) and posting the footage online. The stunt was meant as a genetic flex. Most humans lose the ability to digest lactose after childhood; a mutation called lactase persistence, which evolved in Europe roughly eight thousand years ago, lets carriers keep processing milk throughout their lives. The neo-Nazis were claiming this as proof of racial superiority.

The problem is that the same functional outcome, achieved through independently evolved mutations, appears at high frequency in Kazakhs, Ethiopians, the Tutsi, the Khoisan, and pastoralist communities across the Middle East who adapted to camel milk, not cow's. The racists had found a real genetic difference and read it backward. The science they were citing had already catalogued exactly the populations that disprove their premise; they just hadn't read past the first line.

Rutherford calls this the central danger of our moment. Racism has always borrowed scientific authority, but direct-to-consumer DNA tests have put population genetics into casual conversation, and neo-Nazi forums can circulate academic-sounding arguments overnight. Misreadings travel faster than corrections. They're built on real data about human variation, selectively cropped. That's what makes them harder to dismiss than a slur.

He trained at UCL's Galton Laboratory — named for the Victorian scientist who coined "eugenics" and whose 1873 letter to The Times proposed replacing Africans with Chinese settlers because they were "lazy, palavering (endlessly talking) savages." His case is that the same genetic tradition racists have co-opted has already answered every specific claim they make. The rest of this summary is that answer. It starts with what geneticists found when they actually tried to draw a line around human populations — and why they couldn't.

Skin Color — The Most Intuitive Racial Signal — Is Genetically Incoherent

Sarah Tishkoff's team spent years measuring skin pigmentation in more than 1,500 people across Botswana, Ethiopia, and Tanzania, comparing the results directly to their DNA. The most striking finding involved SLC24A5, a gene whose variant is so reliably associated with light skin in Europeans that it functions as a genetic signature of northern ancestry — one of nearly 200 genes now known to influence pigmentation. Tishkoff found this variant at high frequency across Ethiopia and Tanzania. In those populations, it produces no lightening effect whatsoever. A gene supposed to explain European paleness turns up commonly in some of the darkest-skinned people on Earth, apparently doing something else entirely that hasn't yet been identified.

That finding alone destabilizes the assumption that pigmentation genes sort neatly along racial lines. But then there's the timeline. Many of the variants Tishkoff's study identified had been circulating in human lineages for hundreds of thousands of years. Some predate Homo sapiens itself — already in the gene pool before our species existed, before the dispersal out of Africa, before any of the ancestral populations that racial taxonomy depends on had formed. The genetic diversity underlying what you see when you look at skin color is older than race, older than our species, and distributed across populations in ways that don't map cleanly onto any group.

The intuition that skin is a reliable proxy for deep ancestry feels almost irresistible. It is also, by the evidence, wrong. You're not reading descent when you read complexion. You're reading the surface output of a system with hundreds of ancient variables, operating by rules that have been reshuffling across every human population far longer than any racial category has existed.

The Ancestor Math That Makes Racial Purity Mathematically Impossible

Imagine tracing your family tree backward. Each generation doubles: two parents, four grandparents, eight great-grandparents. Keep doubling for five hundred years and you'd need more than a million ancestral slots. Go back a thousand years and you'd need over a trillion — roughly ten times the total number of humans who have ever existed. The math is obviously broken. Which means the model is wrong.

Family trees aren't trees. Real trees only branch outward. Family trees loop — the same individuals occupying multiple positions as cousins marry cousins across generations. The further back you go, the more ancestors collapse into each other: fewer actual people filling more and more slots. And this collapse happens fast.

Rutherford works out the numbers on Edward III, a fourteenth-century British king. Following his confirmed descendants forward and assuming modest reproduction, Edward would have had roughly 20,500 living relatives by 1600, about half a percent of Britain's 4.2 million people. Now track backward from someone born in 1975. Fifteen generations puts you at 1600, with a maximum of 32,768 ancestral positions to fill. The question: what's the probability that not one of those 32,768 people is in the half-percent who descended from Edward? The calculation — 0.995 raised to the power of 32,768 — equals 4.64 times ten to the negative 72. That's not merely small; it's zero. If you have any British ancestry at all, you descend from Edward III. You also descend from William the Conqueror, Alfred the Great, and every tenth-century European peasant and lord. There is no meaningful distinction between noble and common bloodline at that remove. They're all yours.

Go back further and the collapse becomes total. Geneticists call the isopoint the moment when everyone alive at a given time who reproduced at all became an ancestor of the entire living population. For Europeans, that threshold is around the tenth century CE. Globally, it falls around 1400 BCE. Every human alive today descends from every human alive then who left any offspring.

The logic is pure arithmetic. A pure bloodline, White or any other designation, cannot exist. The math won't allow it. Ancestry doubles backward faster than the past could have contained it. The tree has to loop. It always loops.

Richard Spencer, a prominent American white nationalist, posted his 23andMe results to Twitter showing 99.4% European ancestry. His full profile, which he made publicly visible on the platform, shows North African and Mongolian ancestors as recently as the nineteenth century. He has not commented.

The Olympic 100m Data That Racists Never Finish Reading

Why, if West African ancestry confers a genetic sprinting advantage, have zero South Americans of any ancestry ever competed in an Olympic 100m final?

The transatlantic slave trade transported millions of West Africans to South America, at least as many as were taken to the Caribbean and North America. If that ancestry carries superior sprint genetics, Brazilian and Colombian runners should be competing alongside Jamaicans and African Americans. They're not. They're absent entirely.

The number that stops the genetic argument cold: since the 1980 Moscow Games, the last time white men appeared in an Olympic 100m final, exactly five African men have competed in those same finals. Five, matching white men precisely, with only one breaking ten seconds. The dominant sprinters are African Americans and Caribbeans, descendants of the enslaved. Actual West Africans are nearly as absent from the finals as Europeans.

The slavery selection hypothesis makes a specific prediction: that centuries of slave owners selecting for physical endurance produced descendants with superior athletic genetics, and that advantage should appear wherever those descendants settled. It doesn't. African Americans make up less than ten percent of Major League Baseball players despite that sport requiring explosive speed and throwing power. The supposed genetic advantage is somehow sport-specific and geography-specific, which is not how genes work.

The molecular data puts a ceiling on what genetics can explain. A gene called ACTN3 produces a variant called the R allele (the form linked to fast-twitch fiber production), present in 96 percent of African Americans and 80 percent of white Americans. A real difference. But work through what it actually predicts: a 16-percentage-point gap produces, at most, six elite Black sprinters for every five white ones. The actual ratio in Olympic finals since 1980 is more than ten to one. The gene doesn't begin to explain what's happening on the track.

What does explain it is the same thing that created Finnish dominance in distance running through the first half of the twentieth century: a culture of success, expert coaching, economic incentives, and role models who make the goal look achievable. When that Finnish culture dissolved, the dynasty ended. Finnish DNA hadn't changed. The bodies were identical; the world around them had shifted. Ancestry gives you a body. What happens to it is something else entirely.

IQ Scores Are Rising Too Fast for Genes to Be the Explanation

In the early 1980s, the political scientist James Flynn was working through test scores that made no sense. IQ, meant by many researchers to measure something fixed in the hardware of the mind, had been climbing across every country he examined at roughly three points per decade since the 1930s. He checked again. The rise was real, consistent, and impossible to explain if IQ measured something innate. The pattern became known as the Flynn Effect.

The most striking case is Ireland. In the 1970s, the Irish averaged about 85 on IQ tests, fifteen points below the British mean — the kind of gap race scientists treat as evidence of genetic difference. By the late 1990s, it had closed entirely. The Irish now score on par with Britain and slightly ahead of the United States. Nothing in the Irish gene pool shifted in those two decades. What shifted was the country: mass investment in education, rapid urbanization, better nutrition, and television introducing new cognitive demands into everyday life. A fifteen-point difference that had been cited as proof of genetic hierarchy dissolved within a single generation.

That's where the racial argument collapses. Some sub-Saharan African nations currently average in the low 80s on IQ tests, and race scientists read that as genetic. But European countries before the welfare state, mass education, and modern nutrition showed comparable scores. By Richard Lynn's own data — the source race scientists most often cite — the Netherlands in the 1950s would register around 80 by today's norms. The gap between Western and African averages today mirrors the gap between past and present Europe. If the earlier European gap wasn't genetic, there's no warrant for calling the African one genetic either. The Flynn Effect hasn't arrived uniformly, and where it hasn't, the reason is conditions, not ancestry.

The genetic tools researchers actually use tell the same story. Genome-wide studies identify thousands of DNA variants that correlate with cognitive performance, but those correlations hold only within the population studied. A polygenic score built from European cognitive data cannot explain why European and African averages differ, for the same reason that finding the height variants that separate tall Dutch from short Dutch tells you nothing about why the Dutch are the tallest people in the world. The genetic architecture differs between populations. The tool that confirms IQ is partly heritable within a group cannot explain why groups differ.

The racists borrowed a real instrument. They just can't read it.

The Geneticist Admits He Might Be Biased — Which Is Exactly the Point

The argument that genetics disproves racism is only as strong as the geneticist making it, and Rutherford doesn't claim to be above the problem. He trained at UCL's Galton Laboratory, named for the Victorian scientist who coined "eugenics" and proposed in print replacing African populations with Chinese settlers; Galton's portrait hung in the seminar room. Rutherford is mixed-race. He has been accused of distorting the science out of political commitment or personal stake, and he doesn't wave it away. He admits that bias accumulates in research, that the vocabulary of genetics — "European," "Caucasian" — reinforces categories with no historical basis that the field is supposed to dissolve, and that most large genomic datasets skew toward hospital patients in wealthy countries, a bias researchers rarely acknowledge.

The irony is total: the entire tradition of human genetics was built by racists, for partly racist purposes — and has become the field most responsible for showing that race has no coherent biological foundation. Galton's laboratory became the weapon against him. The founding pseudoscience generated the tools that demolished itself.

So Rutherford doesn't need a perfectly neutral science. He needs an honest one. And what the honest science says is already settled: no genetic hierarchy between populations, no ancestry-to-performance link in sport or cognition, no biological support for racial purity.

Even if future genetics found racial differences we haven't found yet (and there's no evidence pointing that way), the question would remain: would that justify unequal treatment? The rights people are owed don't rest on biology. They never did. What a population averages in any trait doesn't determine what any individual deserves. The empirical case against racism is airtight. The moral case would hold even if it weren't.

Your Fight Is Not With Me — It's With Reality

Here's what's worth sitting with: the racist doesn't need a moralist's rebuttal. He needs someone to finish his own calculation. The sprinting argument stops before the South American blank. The IQ gap stops before the Flynn Effect erases it in a single Irish generation. The purity claim collapses under arithmetic that makes 4.64×10⁻⁷² the probability you don't descend from Edward III. Every specific claim collapses under the evidence it was trying to use.

You don't need any of that to defend human dignity, because dignity was never predicated on biology. Rights don't require a favorable genome. But the empirical case is airtight. Which means the racist isn't just wrong morally. He's wrong on his own terms, in his own field, by his own numbers.