Race science, often called “scientific racism,” is the use of scientific methods and language to argue that human racial groups are biologically distinct and can be ranked by intelligence, behavior, or worth. It is not a legitimate field of science. It is a centuries-old practice of dressing up racial hierarchies in the appearance of objectivity, and modern genetics has thoroughly dismantled its core claims. Humans are more than 99% genetically identical, and there is more genetic variation within any racial group than between different groups.
Where Race Science Came From
Race science emerged during the 18th and 19th centuries, a period of European colonial expansion when self-described experts began classifying human populations into fixed hierarchies. It drew on revolutionary advances in medicine, anatomy, and statistics, as well as distortions of Charles Darwin’s theory of evolution and Gregor Mendel’s laws of inheritance. The central idea was that biological and behavioral characteristics were permanent and unchangeable, and that entire populations could be ranked as superior or inferior based on physical traits.
These classification systems did not arise in a vacuum. The American Association of Physical Anthropologists has stated plainly that the Western concept of race emerged from, and in support of, European colonialism, oppression, and discrimination. Racial categories were constructed over roughly the last five centuries, shifting over time to reflect changing political realities and systems of power. The categories were never neutral or purely observational. They were built to justify exploitation, slavery, and territorial conquest.
Skull Measurements and Early Methods
One of the most well-known examples of race science in practice was the work of Samuel George Morton, a 19th-century Philadelphia physician. Morton collected skulls from around the world and measured their internal volume by filling them with white pepper seeds (and later lead shot). He used these measurements as a proxy for brain size and, by extension, intelligence, producing rankings that conveniently placed white Europeans at the top.
The biologist Stephen Jay Gould later reanalyzed Morton’s published data and identified a pattern of inconsistencies, miscalculations, and procedural errors that consistently favored Morton’s preexisting beliefs. Gould argued that seed, unlike lead shot, could easily be manipulated: Morton may have unconsciously packed more seed into European skulls and less into others, systematically inflating his preferred group’s scores.
Even before Morton published, the German anatomist Friedrich Tiedemann had conducted a similar study and reached the opposite conclusion. After measuring 248 skulls from five racial groups, Tiedemann found that the wide and overlapping ranges of cranial capacity across groups suggested no meaningful racial differences in brain size or intelligence. His 1836 paper stated that “neither anatomy nor physiology can justify our placing [any group] beneath the Europeans in a moral or intellectual point of view.” Race science did not follow the evidence. It selected the evidence that fit a predetermined answer.
Eugenics and Real-World Consequences
Race science was never just an academic exercise. In 1883, the English statistician Francis Galton coined the term “eugenics,” defining it as the study of factors that could improve or impair “the racial qualities of future generations.” Galton claimed that health, disease, and intellectual characteristics were all determined by heredity and race, and his ideas spread rapidly through Europe and the United States during the 1870s and 1880s.
In the U.S., eugenics became government policy. A 1922 “model law” for compulsory sterilization served as the legal template for forced sterilization programs across the country. The U.S. Supreme Court upheld Virginia’s sterilization statute, effectively giving every state permission to do the same. By 1936, when the scientific community finally condemned the practice, over 60,000 forced sterilizations had already been performed, overwhelmingly targeting poor people and African Americans confined to mental institutions. Nazi Germany’s own eugenics programs were explicitly modeled on American laws.
Why Genetics Disproved Biological Race
The completion of the Human Genome Project in 2003 confirmed what population geneticists had long suspected: humans are more than 99% identical at the DNA level, and there is no genetic basis for the concept of discrete biological races. The variation that does exist between people follows smooth geographic gradients rather than falling into sharp clusters that align with racial categories.
One of the clearest demonstrations of this comes from a concept called “non-concordance.” If races were real biological groupings, you would expect the traits used to define them to cluster together consistently. They don’t. Skin color, for instance, is an adaptation to ultraviolet radiation. People in tropical Africa and Melanesia (on opposite sides of the world) independently evolved dark skin because both regions have intense UV exposure. Despite looking similar in this one trait, Africans and Melanesians are among the most genetically differentiated human populations on earth. Different adaptive traits, such as skin color, blood type, and the ability to digest lactose, each follow their own geographic pattern shaped by local environmental pressures. No single set of traits carves humanity into the same groups.
When geneticists measure overall genetic differentiation between continental populations, the values are extremely low and increase smoothly with geographic distance. There are no sudden jumps or boundaries that would indicate distinct biological races. Using any standard scientific threshold for defining a subspecies or race, humans simply do not qualify.
IQ Claims and Their Problems
A recurring claim in race science is that observed differences in average IQ scores between racial groups reflect innate genetic differences in intelligence. This argument has been a fixture of the field since at least the 1960s and was popularized by books like “The Bell Curve” in 1994.
The most common counterpoint has been the Flynn Effect: the well-documented phenomenon that IQ scores rise substantially over time within all populations, sometimes by 15 to 20 points per generation. Since these gains happen far too quickly to be genetic, they demonstrate how powerfully environment shapes test performance. Proponents of genetic explanations have pushed back, arguing that the Flynn Effect operates on different components of IQ than those that show racial gaps. But this debate itself highlights the core problem: IQ scores are entangled with socioeconomic conditions, educational access, test familiarity, and structural inequality in ways that make it impossible to isolate a genetic signal for group differences. The environmental factors that differ between racial groups in stratified societies (wealth, nutrition, exposure to pollution, school quality) are precisely the factors known to influence cognitive development.
Race Science Still Embedded in Medicine
One of the most consequential legacies of race science is that racial assumptions became encoded in medical tools still used today. For years, the formula used to estimate kidney function included a “race correction” that automatically inflated scores for Black patients by roughly 16%. The justification was a biological claim that Black Americans have greater muscle mass, but the adjustment had a concrete harmful effect: it made Black patients appear healthier than they were, delaying diagnoses of kidney disease and pushing back eligibility for transplants.
Similar corrections existed in lung function testing. A 19th-century study reported a 13% difference in lung capacity between racial groups, and that figure was eventually built into the software of spirometers worldwide. The effect was to raise the bar for clinical diagnosis in Black and Asian patients, masking the role of actual health drivers like poverty, pollution exposure, and structural racism. In obstetrics, a widely used calculator for predicting success of vaginal birth after cesarean section assigned Black and Hispanic women a 15 to 18% lower likelihood of success than white women, with no clear biological basis for the adjustment.
Many of these tools are now being revised or replaced with race-neutral versions, though the transition itself introduces new complications. Removing race from a cardiovascular risk calculator, for example, maintained overall accuracy but halved the estimated risk for Black adults, potentially reducing their access to preventive medications. Untangling race from medicine requires replacing it with more precise variables, such as genetics, socioeconomic status, and environmental exposures, rather than simply deleting it.
Why It Persists
Race science persists not because the evidence supports it, but because it offers a simple, seemingly objective explanation for social inequalities that are actually produced by history, policy, and economics. If group differences in health, wealth, or education can be attributed to biology, then the systems producing those differences need not change. This is the function race science has served since the 18th century, and it is the function it continues to serve when recycled in online forums, opinion columns, or poorly designed studies that treat race as a biological variable rather than a social one.
The scientific consensus is unambiguous. The American Society of Human Genetics, the American Association of Physical Anthropologists, and the researchers behind the Human Genome Project all agree: race as commonly understood is a social and political construction, not a biological reality. Human populations vary genetically, but that variation does not sort into the discrete, hierarchical categories that race science claims to measure.