Ethnicity is not biological. It is widely recognized by geneticists, anthropologists, and federal agencies as a social construct built from shared cultural factors like language, religion, cuisine, ancestry, and nationality. That said, the relationship between ethnicity and biology is more nuanced than a simple yes or no, because ethnic groups can share certain patterns of genetic ancestry, even though ethnicity itself is defined by culture, not DNA.
What Ethnicity Actually Refers To
Ethnicity describes the cultural identity that communities build around shared traditions, history, language, and geographic origins. A person’s ethnicity can encompass what foods they grew up eating, what language they speak at home, what religious practices their family follows, and what national or regional heritage they identify with. These are all learned and inherited socially, not genetically.
Importantly, ethnicity can change over the course of a person’s life. Someone might shift how they identify as their community ties evolve or as they move between countries. A racially Black Dominican adolescent in the United States, for example, might identify ethnically as Dominican based on her family’s cultural traditions and Spanish language, while simultaneously navigating racial categories that other people assign to her based on appearance. This flexibility is a clear sign that ethnicity operates in the social world, not the biological one.
The U.S. government’s classification system reflects this understanding. In 2024, the Office of Management and Budget revised its standards to combine race and ethnicity into a single question with seven categories: American Indian or Alaska Native, Asian, Black or African American, Hispanic or Latino, Middle Eastern or North African, Native Hawaiian or Pacific Islander, and White. Respondents can select multiple categories. These groupings are administrative tools for data collection, not descriptions of distinct biological populations.
Why Genetics Doesn’t Map Neatly Onto Ethnicity
The strongest evidence against ethnicity being biological comes from population genetics. About 85 percent of all human genetic variation exists within any given population, while only about 15 percent of variation exists between populations. Two people from the same ethnic group can be more genetically different from each other than either one is from someone in a completely different ethnic group on the other side of the world.
A measurement called the fixation index (Fst) quantifies how genetically distinct two populations are from each other. When researchers compare human subpopulations to their nearest continental-scale group, the values fall below 3 percent. Even comparisons between populations on different continents stay under 5 percent. For context, these numbers are remarkably low. They tell us that the genetic boundaries between human groups are blurry and shallow, not the sharp divisions that ethnic or racial categories might suggest.
The National Human Genome Research Institute has noted that researchers across disciplines often use population descriptors “inconsistently and inappropriately” to capture what is actually a continuous pattern of human genetic variation. In other words, human genetics doesn’t come in neat packages that line up with the ethnic labels on a census form.
Where Ethnicity and Genetics Do Overlap
None of this means that ethnic groups are genetically identical to one another. People who share an ethnic background often share geographic ancestry, and geographic ancestry does correlate with certain genetic patterns. The key distinction is that ethnicity is a rough, imperfect proxy for ancestry, not a biological category in itself.
A study of a multiethnic population in New York City illustrates this well. When researchers compared people’s self-identified race and ethnicity to their actual genetic ancestry markers, the results were messy. Self-identified White participants had genetic ancestry that was about 75 percent European. Self-identified Black participants had ancestry that was roughly 78 percent African. So far, a reasonable correlation. But self-identified Hispanic participants told a more complicated story: their genetic ancestry averaged 29 percent European, 26 percent African, and 45 percent Native American, with enormous variation from person to person. Even within the Hispanic category, someone who identified as Black Hispanic had about 56 percent African ancestry, while someone who identified as White Hispanic had about 49 percent Native American ancestry and only 31 percent European.
The takeaway is that self-identified ethnicity gives you a general hint about someone’s geographic ancestry, but it’s far from precise, and for some ethnic groups it barely narrows things down at all.
Why Medicine Still Uses Ethnic Categories
One reason this question keeps coming up is that ethnicity does show up in medical contexts. Certain genetic variants that affect how the body processes medications occur at different frequencies in different populations. The liver enzymes responsible for breaking down many common drugs, for instance, have known genetic variants whose distribution differs across ethnic groups. This can translate into real differences in how effective or how risky a given medication is for people of different backgrounds.
But this doesn’t make ethnicity biological. It means that ethnic groups, because they partially track with geographic ancestry, can serve as an imperfect shortcut when individual genetic testing isn’t available. A doctor who notes your ethnicity is really making a rough guess about your ancestry, which is itself a rough guess about which genetic variants you might carry. The ideal approach is individual genetic testing, which bypasses the guesswork entirely.
How Social Experiences Can Create Biological Effects
There is one more layer to this question that often gets overlooked. The social experience of belonging to a particular ethnic group can produce real biological changes, not because ethnicity is encoded in DNA, but because the environments and stressors that ethnic groups face leave physical marks on the body.
Experiences of discrimination, trauma, and adversity trigger stress responses that affect the brain, the immune system, and the chemical tags that sit on top of DNA and influence how genes are expressed. These tags, known as epigenetic modifications, can persist across generations. Research suggests that grandchildren and great-grandchildren can be negatively affected by ancestral traumas they were never directly exposed to. This means that the health disparities observed between ethnic groups are partly biological in origin, but the biology was created by social conditions like racism and poverty, not by ethnicity itself.
This distinction matters. If you assume ethnic health differences are “just genetic,” you might conclude they’re inevitable. If you recognize that social environments shape biology across generations, those differences become something that better policies and reduced discrimination could actually change.
The Short Answer
Ethnicity is a social and cultural construct. It is not a biological category, and no major scientific institution treats it as one. However, because ethnic groups often share overlapping geographic ancestry, there are statistical correlations between ethnicity and certain genetic patterns. These correlations are loose, vary enormously between individuals, and are far weaker than most people assume. The 85/15 rule in human genetics holds: the vast majority of genetic diversity exists within ethnic groups, not between them.