By Michael Yudell

At the dawn of the 21st century, the idea of race - the belief that the peoples of the world can be organized into biologically distinctive groups, each with their own physical, social, and intellectual characteristics - is understood by most natural and social scientists to be an unsound concept. The way scientists think about race today, after all, is different than it was in the wake of the Civil Rights Movement when some promoted black genetic inferiority as an argument against egalitarian social and economic policy and certainly different than one or two centuries ago, when scientific justifications for slavery and later Jim Crow were articulated. In other words, race, its scientific meaning seemingly drawn from the visual and genetic cues of human diversity, is an idea with a measurable past, identifiable present, and uncertain future. These changes are influenced by a range of variables including geography, politics, culture, science, and economics.

Today, despite the growing consensus among scientists that race is not a useful classificatory tool, an understanding of human difference and diversity remains a hallmark of contemporary scientific practice. This presents a seeming contradiction: how can one study human difference without talking about race? On the one hand, beginning in the 1930s, advances in population genetics and evolutionary biology led many to conclude that the race concept was not a particularly useful or accurate marker of biological difference. By the 1970s, many prominent biologists, including Richard Lewontin and Stephen Jay Gould, came to see the race concept as a deeply flawed way to organize human genetic diversity that is inseparable from the social prejudices about human difference that spawned the concept in the 18th century and have accompanied its meaning since.1 Historians and social scientists believe that race is socially constructed, meaning that the biological meaning of race has been constrained by the social context in which racial research has taken place.

'Race types," from Maury’s New Complete Geography, 1906.

On the other hand, because studying genetic differences can improve our understanding of human evolution, disease, and development, the relationship between genetics and human diversity remains an ongoing area of scientific inquiry. The challenge has been to develop a new scientific terminology and methodology that finds meaning in the study of human difference without recapitulating outmoded and racist notions often associated with the concept of race itself.  Some scientists have developed novel ways to measure difference between various human populations, including using ancestry, ethnicity, and population as replacements or surrogates for race. Others, however, remain steadfast in their belief that technological and methodological improvements now allow an examination of racial difference with increasing precision that is disconnected from any social prejudices.

Ever since Thomas Jefferson wrote in the Declaration of Independence that "all men are created equal," America has struggled with the chasm between this Jeffersonian ideal and the realities of the American experience. Jefferson himself was the author of some of America's earliest ideas about race and science. In 1787, little more than a decade after he had penned the Declaration, Jefferson suggested in his work on the natural history of Virginia, Notes on the State of Virginia, that the difference between the races "is fixed in nature" and hypothesized that blacks were "originally a distinct race."2 The contradiction between the Declaration and Notes may be understood, however, by Jefferson's view of humanity itself. If blacks were of a separate creation, and set apart from the definition of "all men," then the equality set out in the Declaration did not apply to all.

Historian Frank Snowden, looking at black-white contact before the sixth century A.D. found that although there is an "association of blackness with ill omens, demons, the devil, and sin, there is in the extant record no stereotyped image of Ethiopians as the personification of demons or the devil."3 In ancient Greece and Rome "the major divisions between people were more clearly understood as being between the civic and the barbarous," between the political citizen and those outside of the polis, and not between bloodlines or skin color.4 Most scholars now accept the viewpoint that in the ancient world "no concept truly equivalent to that of 'race' can be detected in the thought of the Greeks, Romans, and early Christians."5 Rooting human variation in blood or in kinship was a relatively new way to categorize humans. The idea gained strength towards the end of the Middle Ages as anti-Jewish feelings, which were rooted in an antagonism towards Jewish religious beliefs, began to evolve into anti-Semitism. These blood kinship beliefs rationalized anti-Jewish hatred instead as the hatred of a people. For example, Marranos, Spanish Jews who had been baptized, were considered a threat to Christendom by virtue of their ancestry because they could not prove purity of blood to the Inquisition.

Beginning in the eighteenth century, at the height of the Age of Enlightenment in Europe, these ideas were applied to explaining the diversity of humankind. This was driven in part by the experiences with new peoples during colonial exploration, the need to rationalize the inferiority of certain peoples as slavery took hold in European colonies, and the development of a new science to assess and explain diversity in all species. The Swedish botanist and naturalist Carolus Linnaeus also made lasting contributions to the race concept at this time. Linnaeus's "natural system," which became the basis for the classification of all species, divided humanity into four groups: Americanus, Asiaticus, Africanus, and Europeaeus. But while the term race existed before the 18th century, mostly to describe domesticated animals, it was introduced into the sciences by the French naturalist Georges-Louis Leclerc, Comte de Buffon in 1749. Buffon saw clearly demarcated distinctions between the human races that were caused by varying climates. Buffon's climatological theory of difference was infused with notions of European superiority. To Buffon, the natural state of humanity was derived from the European, a people he believed "produced the most handsome and beautiful men" and represented the "genuine color of mankind."

The Swedish botanist and naturalist Carolus Linnaeus also made lasting contributions to the race concept at this time. Linnaeus's "natural system," which became the basis for the classification of all species, divided humanity into four groups: Americanus, Asiaticus, Africanus, and Europeaeus.

If racial science is science employed for the purpose of degrading a people both intellectually and physically, then beginning in the 19th century, American scientists played an increasingly active role in its development. Scientists like Samuel Morton, Josiah Nott, and George Gliddon offered a variety of explanations for the nature of white racial superiority meant to address the nature of physical and intellectual differences between races, the "natural" positions of racial groups in American society, and the capacity for citizenship of non-whites.

At the core of this work, known as the American School of Anthropology, was the theory of polygeny, the belief that a hierarchy of human races had separate creations. Samuel Morton's experiments on cranial capacity and intelligence sought to demonstrate this theory. Morton collected hundreds of skulls from around the globe, measured their volume, and concluded that the Caucasian and Mongolian races had the highest cranial capacity and thus the highest levels of intelligence, while Africans had the lowest cranial capacity and thus the lowest levels of intelligence.

More than a century after Morton's death, the evolutionary biologist Stephen Jay Gould, using Morton's same experimental material and methods, could not replicate the earlier findings. Gould concluded that Morton's subjective ideas about race difference influenced his methods and conclusions, leading to the omission of contradictory data and to the conscious or unconscious stuffing or under-filling of certain skulls to match his pre-ordained conclusions.6 Indeed, the case of Samuel Morton illustrates how social conceptions of human difference shape the science of race.

At the dawn of the 20th century, explanations for racial difference based on measurable and observable physical traits such as cranial capacity and skin color gave way to a whole new way of thinking about the subject. Race instead came to be understood as a reflection of unseen differences that the scientists of the time attributed to the recently discovered factors of heredity. As ideas about racial differences became rooted in biology, genetics came to provide the formative language of modern racism.

This geneticization of race - the idea that racial differences in appearance and complex social behaviors can be understood as genetic distinctions between so-called racial groups - was shaped, in large part, by the eugenics movement. According to Francis Galton, the founder of the movement, eugenics promised to give "the more suitable races or strains of blood a better chance of prevailing over the less suitable."7 This could be done either through positive eugenics in which certain groups were encouraged to breed with one another; or through negative eugenics in which certain groups or individuals would be denied the right to reproduce - either through sterilization, as was the case in the United States, or through genocide, as was the case in Nazi Germany. Under the guise of this biological banner, eugenic racial science exerted a diverse and far-reaching influence. It became a powerful ideological force in Nazi Germany, influenced the creation of eugenic sterilization laws in the United States that resulted in at least 30,000 sterilizations, stoked racial hatred in early 20th century America, and became a scientific buttress of 20th century American racial ideology. For the first three decades of the 20th century, many geneticists advocated eugenic ideas and helped to shape the movement.

Beginning in the 1930s, an increasing number of geneticists, anthropologists, and social scientists began moving away from typological and eugenic descriptions of human difference to view races through the lens of population genetics and evolutionary biology. This approach rejected a eugenic notion of fixed genetic differences between so-called racial groups, and instead understood human races as dynamic populations distinguished by variations of the frequency of genes between populations. By rooting the meaning of race in genetic variation it became more difficult (though still possible) to argue that one race or another had particular traits specifically associated with it, or that one individual was typical of a race. Furthermore, the four or five racial groups identified by 18th and 19th century scientists now varied depending upon the genes and traits examined by geneticists. Theodosious Dobzhansky, the evolutionary biologist whose work between the 1930s and 1970s had a tremendous influence on the way that scientists thought about race, concluded that the number of human races was variable depending upon what traits were being examined. In fact, he believed that the concept of race in the context of population genetics and evolutionary biology was a scientific tool for making genetic diversity intelligible and manageable in scientific study. In other words, while human differences are real, the way we choose to organize those differences is a methodological decision and not one that reflects an underlying evolutionary hierarchy or the conservation of racialized traits through the admixture of populations. This new approach was brought about by new findings in genetics that demonstrated genetic variation was much more common within species than once thought and by the development of what is known as the evolutionary synthesis in biology, a "Darwinian fusion" of population genetics, experimental genetics, and natural history.8 Finally, changes in the concept of race were influenced by a growing cadre of scientists who were generally more liberal on matters of race than their predecessors.

At a June 2000 Rose Garden ceremony, President Bill Clinton, flanked by genome sequencers Francis Collins and Craig Venter, announced the completion of a draft sequence of the human genome. Collins, head of the National Human Genome Research Institute, and Venter, then President of Celera Genomics, offered their genomic data to the world - enhancing our understanding of human biology and holding the promise of to helping public health and medical professionals prevent, treat, and cure disease. On that day Venter and Collins emphasized that their work confirmed that human genetic diversity cannot be captured by the concept of race and demonstrated that all humans have genome sequences that are 99.9% identical. At the White House celebration Venter said "the concept of race has no genetic or scientific basis."9 A year later, Collins wrote: "those who wish to draw precise racial boundaries around certain groups will not be able to use science as a legitimate justification."10 Yet, since the White House announcement, there has been an increase in claims that race is a biologically meaningful classification.

The upsurge of claims that race is a useful taxonomic concept for humans seems to be driven by several factors. First, genomic technology has enhanced our ability to examine the 0.1% of nucleic acids in the human genome that, on average, vary between individuals. Some scientists are relying on the race concept to make sense of the genetic variation in this small sliver of our genomes. Second, the history of the biological race concept suggests that race is deeply embedded in scientific thought and that racialized thinking shaped genetics in the 20th century. This history continues to shape scientific thinking about human difference. Finally, the critical task of understanding and reducing known disparities in health has researchers looking at all possible explanations, including genetic ones, for disparities in health outcomes. Fueled by programs such as the National Institutes of Health's "Healthy People 2010" and CDC's "Racial and Ethnic Approaches to Community Health," the search for the underlying causes of these disparities is a national healthcare priority. The renewed focus on race and genetics suggests that an analysis of the complex relationship between individuals, populations, the environment, and health may be surrendered to a racial worldview.

It would be silly to think that science will somehow extricate us from a racial quagmire. Despite advances in scientific thinking on race, racism and the belief in races persist. Racism is too complicated to be eradicated by science alone. Nonetheless, scientists do have much to offer to the debate over the nature of race and racial classification, and we would all be the better for listening to what they are saying. Geneticists Kelly Owens and Mary-Claire King recognize this, writing that: "Of course, prejudice does not require a rational basis, let alone an evolutionary one, but the myth of major genetic differences across 'races' is nonetheless worth dismissing with genetic evidence."11                              


Michael Yudell, PhD, MPH, is an Assistant Professor in the Department of Community Health and Prevention at the Drexel University School of Public Health. Dr. Yudell is the author, with Rob DeSalle, of Welcome to the Genome: A User's Guide to the Genetic Past, Present, and Future (2004). He is currently completing the book Making Race: Biology and the Evolution of the Race Concept in 20th Century American Thought.



1. Histories of the race concept include: Bruce R. Dain, A Hideous Monster Of The Mind: American Race Theory In The Early Republic. (Cambridge, Mass.: Harvard University Press, 2002); Audrey Smedley, Race In North America: Origin And Evolution Of A Worldview. (Boulder, Colo.: Westview Press, 1999); William Stanton, The Leopard's Spots: Scientific Attitudes Toward Race In America, 1815-59. (Chicago: University Of Chicago Press, 1960); Nancy Stepan, The Idea Of Race In Science: Great Britain, 1800-1960. (Hamden, Conn.: Archon Books, 1982); Elazar Barkan, Retreat Of Scientific Racism: Changing Concepts Of Race In Britain And The United States Between The World Wars. (New York: Cambridge University Press, 1992); Stephen Jay Gould, The Mismeasure Of Man. (New York: Norton, 1996).

2. Thomas Jefferson, Notes on the State of Virginia (Chapel Hill: University of North Carolina Press, 1955) pp.138-140, 143.

3. Frank M. Snowden, Before Color Prejudice: The Ancient View of Blacks (Cambridge: Harvard University Press, 1983) p.107.

4. Ivan Hannaford, Race: The History of an Idea in the West (Washington, D.C.: Woodrow Wilson Center Press, 1996) pp.14, 17-60.

5. George M. Fredrickson, Racism: A Short History. (Princeton: Princeton University Press, 2002) p.17

6. Stephen J. Gould, Mismeasure of Man (New York: Norton, 1996), p. 70.

7. Francis Galton, Inquires Into Human Faculty and Its Development (New York: MacMillan and Company, 1892) p.25.

8. Stephen Jay Gould, "Introduction," Genetics and the Origin of Species by Theodosius Dobzhanksy (New York: Columbia University Press, 1982 ed.) p.xxi.

9. Rick Wiess and Justin Gillis, "Teams Finish Mapping Human DNA," Washington Post (June 27, 2000) p.A1.

10. F.S. Collins and M.K. Mansoura, "The Human Genome Project: Revealing the Shared Inheritance of All Humankind," Cancer 92(2001) pp.S221-S225.

11. N. Risch, E. Burchard, E. Ziv, and H. Tang, "Categorization of Humans in Biomedical Resaerch: Genes, Race, and Disease," Genome Biology. 3(2002) pp.2007.1-2007.12.

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