POINT: RACE IS A SOCIAL CONSTRUCT, NOT A GENETIC INDICATOR, says Troy Duster, professor of sociology at New York University and the University of California at Berkeley and former president of the American Sociological Association. He specializes in the sociology of science and in issues of race and ethnicity.

Since at least the 1600s, scientists have grouped humans according to various racial taxonomies and have tried without success to link those categories to inherent biological characteristics. For example, biologists spent much of the first half of the twentieth century seeking a connection between race and blood types. By the 1970s, we had finally reached wide scientific consensus that race is a social construct with little meaning in biological terms—racial categories are superficial and tell us virtually nothing about our underlying physiology. But today we are once again at risk of giving race a false biological reality, this time based on differences between groups’ DNA markers.

Last June the Food and Drug Administration approved the use of BiDil, a combination heart drug, for use by African Americans. This is the first time a drug has been earmarked for a specific ethnic group. Now other pharmaceutical companies are following the example of NitroMed, BiDil’s maker, and seeking approval for medicines that appear to work in a certain group—usually after the drug has failed to show effectiveness in the general population (though BiDil wasn’t tested for that). This advent of “racialized medicine” is a slippery slope for science and will inevitably lead to poor medical decisions.

The promise of personalized medicine, which seeks to design therapies that benefit individuals who carry a certain genetic characteristic, is bright. But race is a poor proxy for the wide genetic variability among humans. In the best of worlds, physicians would screen patients for the specific gene against which BiDil is effective. However, it is far more convenient for drug companies to market to an entire racial group. Many blacks who get BiDil won’t need it because they don’t have the biological condition in question, while whites who should get the drug won’t. Of the 100,000 documented medical mistakes each year in this country, about 11,000 are misdiagnoses of heart problems. This drug could lead to more such errors.

The wider danger of racialized drugs is that we will lose sight of the social effects of race on physiology. Consider the finding that black Americans are more likely than whites to have hypertension. A biologist ignorant of sociology might blame a genetic difference. But we know that stress can cause hypertension and that stress may result from discrimination, living in unsafe neighborhoods and other societal factors. It seems reasonable to conclude that black people experience hypertension in great numbers at least in large part because of the stress of being black in America. In fact, when we look at those of African descent around the globe, we find some communities where hypertension rates are very low.

Medicine shouldn’t be race-blind. But we need to study racial disparities in health without treating race as a biological category. Social and cultural factors are far more important.

COUNTERPOINT: Race correlates highly with genetic variation, says Neil Risch, professor of human genetics and director of the Center for Human Genetics at the University of California at San Francisco. He specializes in the genetic epidemiology of diseases in ethnic populations.

Social factors undoubtedly play a role in racial and ethnic disparities in health. But we shouldn’t dismiss the possibility that genetic factors can also contribute, including in the evaluation of drug efficacy and side effects.

Racial and ethnic categories are social phenomena, but they also have real genetic meaning. Race, in particular, is strongly related to an individual’s continental ancestry, the level at which the greatest genetic variations between populations are found. When people describe their race according to categories used in the 2000 U.S. census, the results show a very high correlation with what one would find in grouping the same individuals by screening genetic markers. Even African Americans and Hispanics, who typically have mixed ancestry, can be grouped into discrete genetic clusters. Many ethnic categories—even those with common continental ancestry, such as the Amish, French Canadians and Finns—have population-specific genetic variants, many of which have been proven to play a role in disease and drug response.

To not take these differences into account harks back to the days when medicine ignored gender. Just as it isn’t acceptable to study the etiology of heart disease only in men, it shouldn’t be acceptable to extrapolate the results of a study of one ethnic group to the population at large. For example, at least two genetic deficiencies cause an adverse reaction to irinotecan, a drug used to treat colorectal cancer. One deficiency is more common in whites and blacks, the other in Asians. Any study that looked at only white patients would have found just one deficiency, overlooking the potential risks for Asians.

I haven’t studied BiDil, but I support the principle of race-specific medicines—provided scientists have proven that the drug is effective in some groups but not others. Incidentally, such organizations as the Association of Black Cardiologists and the National Medical Association, which represents African Americans, support race-specific use of BiDil. My larger concern is that drugs aren’t tested in enough separate ethnic groups; for example, African Americans might not be the only population group that could benefit from BiDil. For that reason alone, drug companies should ensure that members of all ethnic groups are well represented in studies.

We need to recognize that we’re dealing with a legacy of unequal access to medical care for minorities in this country. If advances in genetic knowledge cause a revolution in medicine, it’s important that all groups benefit from it.