Why DNA Tests Can’t Decide Who’s “White”

How white supremacists misunderstand the concept of race and usage of ancestry tests

Recently, I found myself debating a white supremacist who insisted only “white people” should enjoy certain rights: the right to enter a country as an immigrant, claim refugee protection, or hold the highest public office.

When I asked how he’d decide who counts as “white,” he said: “Easy — anyone of European ancestry. DNA tests are so accurate now — they’ll prove it.”

At first, that might sound scientific. But scratch the surface, and the whole idea collapses into nonsense.

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How ancestry tests actually work

First, your DNA doesn’t contain segments labeled “European,” “African,” or “Chinese.” There’s no genetic switch for “whiteness.” Nearly all human genes exist in every population — humans are about 99.9% identical at the DNA level.

What ancestry tests measure is statistical similarity — and how your DNA clusters with other people.

A company builds reference groups — thousands of people whose families lived mostly in the same region (like Norway, Poland, or Italy) for many generations.

They scan for genetic markers (SNPs) that differ in frequency between these groups. For example, one marker might appear in 40% of Germans, 65% of Norwegians, 50% of Swedes.

The test then checks which patterns of markers your DNA shares with these groups — and runs the math to see which clusters your DNA segments group with most strongly.

The result is a probability estimate:

“54% match with our Norwegian cluster, 30% German, 16% British.”

So, your DNA doesn’t come with a single hidden meter showing “how white you are.”

It shows which population clusters you most resemble — always with some fuzziness.

These matches don’t literally measure how many “liters” of Spanish or North African DNA you contain — they compare how your genome fits multiple clusters at once. Because clusters overlap, you can match several at the same time.

A good analogy is how a neural network recognizes handwritten digits:

It might say a digit has an 80% match for “7” and a 35% match for “1.” It’s not because the digit is partly “one” and partly “seven” — it’s because those digits share shapes. The system just finds the best statistical fit.

In the same way, ancestry tests don’t find “pure” genes for Spain or North Africa. They find stretches of DNA where certain markers are more common in one group than another. Very few markers are unique to a single population.

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Migration makes clusters blurry

Europe’s own DNA shows why the idea of measuring “whiteness” precisely breaks down. Take Spain, Portugal, Sicily, or parts of southern Italy. History tells the story: North African Moors ruled parts of Iberia for centuries; Sicily and southern Italy were crossroads for Greeks, Arabs, North Africans, Normans.

As a result, many people in these regions today carry some North African or Near Eastern ancestry — often 5–20% in genetic studies. So what does that make them? Are they “less European”? Should Spain be banned from Europe?

It gets blurrier when you flip it around: if you test a North African whose family historically traded with Andalusia, they might show a moderate “Spanish match” — not because their grandparents came from Spain, but because those regions blended genes back and forth for centuries.

And DNA tests don’t show the direction of mixing. If the gene flow went south instead of north — say, Iberian people migrated to North Africa in large numbers — then modern Spanish people could still show a “North African match,” even if their ancestors never lived in North Africa.

You see the same blur along other borders: Greece and Turkey, or the Balkans and the Middle East. A Greek family that matches Turkish reference clusters doesn’t automatically mean they “have Turkish blood.” It could be that a nearby Turkish region has Greek ancestry from past migrations — or the other way around.

So these clusters are real — but human movement means they fade into each other over time. The DNA doesn’t come with a tidy label saying who crossed which line first.

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Finns and Estonians

Let us look at the North instead of the South. Modern Finns and Estonians carry noticeable Siberian and Uralic ancestry — genetic traces that come from ancient migrations of peoples from the northeast. Does that make them “less European” than, say, a Swede or a Dane? Are they 50% white and 50% something else? Of course not — they’re just Finnish or Estonian.

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The “California cluster” experiment

Push this logic to the present: imagine you build a California cluster today.

California is wildly mixed — people with European ancestry, Latino heritage, East Asian roots, African ancestry, Middle Eastern immigrants — all living in the same place.

You gather DNA from a thousand Californians and average it into one reference group.

Now run a test on a random Norwegian. They might come back “10% Californian.” Why?

Because they share Northern European DNA with part of California’s population — the piece descended from settlers, Scandinavians, Germans, Brits.

Does that mean Norway was settled by Californians? Should Norway open the border for a “return migration?”

Obviously not — the match is real math, but the cluster is just a convenient average hiding older differences.

So what does this show?

It shows you can always make a cluster — but whether it makes sense depends on whether the people in that group really share a single, historically stable population history.

When white supremacists talk about “Europeans” or “whiteness,” they’re basically pointing at a cluster that is tighter than California today. Europe’s population structure is older — people mostly mixed within Europe for thousands of years, so you do get clearer blobs on a DNA plot.

So fine — Europeans form a “realer” cluster than “California.”

But here’s the twist: modern Italy is not so different from the California example.

Italy lumps together deep regional clusters:

• Sardinians, who form a clear island population.

• Northern Italians with heavy Central European input.

• Southern Italians and Sicilians with layers of Greek, Arab, North African ancestry.

So when a DNA test says you’re “40% Italian,” it’s often doing exactly what the “California cluster” does: blending distinct older groups into one convenient average.

The number is real — but the label can be as misleading as calling your DNA “Californian.”

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When DNA becomes a gate

If you tie rights — immigration, citizenship, holding office — to a DNA percentage, you create an obvious incentive to stretch the boundary.

You can’t just throw wildly different people into a “white” cluster — the math splits them into separate blobs immediately. Nobody’s sneaking Nigerians or Han Chinese into “Norwegian.” The structure shows up whether you want it or not.

But you can quietly expand the edges:

Oversample border regions, coastal towns, or groups that overlap. Fold in Turks with deep Greek ancestry, Berbers with Mediterranean ties, or Anatolian regions with heavy European gene flow.

Nothing fake — just careful choices about where to look, who to call “typical,” and which parts of the map to highlight or hide.

Companies do this all the time — not out of conspiracy, but because there’s no hard rule for exactly who to include. Reference groups are real, but they’re built by people with practical limits, funding constraints, and sometimes political pressures.

So if “whiteness” becomes a legal gate, one company might say you’re 95% white, another says you’re 80% — both are “true” for their version of the cluster. Which result does the border guard trust? The court? The politician?

If people can shop for whichever test certifies their “whiteness,” companies have every reason to compete: stretch the reference group just enough to cover more customers. Or a government might tighten it, slicing off edge cases it doesn’t want. Same DNA — different line.

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The real lesson

The fundamental catch is that while there is an objective way to measure how close your DNA is to the center of a population cluster — that center is not some timeless, fixed point. It shifts depending on who gets sampled, which regions are included, and how far the cluster’s edges are allowed to stretch.

Ancestry tests were never designed to measure “whiteness” like a pass/fail stamp. They estimate how similar your DNA is to a reference group — but that reference is a moving average, not a natural border.

Your score can change as companies update their panels, add new regions, or adjust the math.

DNA tests are amazing for exploring how humans migrated, mixed, and built new cultures. But they’re terrible at drawing neat, final lines between people.

Race is a story we map onto the messy, flowing web of human genes. You can’t carve that flow into perfect boxes with a lab kit and a probability score.

Our genomes don’t carry flags or borders. They carry patterns, overlaps, and reminders that people have always moved and blended more than any story about “pure” types likes to admit.

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So next time someone claims a DNA test can say who deserves to belong — remind them: there’s no “white gene.” Just blurry clusters, ancient trade routes, wandering tribes, and a global family tree that refuses to fit inside neat boxes.

DNA can tell us where our ancestors might have walked — but it cannot decide who gets to stand here now.

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NOTE: This is revision of an earlier article and I will likely make further revisions as this is tricky topic and easy to leave out important details or oversimplify things.