Debate over the proper use of racial and ethnic categories in biomedical research has raged in recent years. With the Human Genome Project showing that human beings are overwhelmingly alike genetically, exhibiting more genetic variation within supposed “races” than between them, many have come to doubt the scientific utility of such categories. Yet federal authorities use Directive 15 from the Office of Management and Budget (OMB) to mandate the continued use of such categories in research. Moreover, researchers studying health disparities argue that data collection using racial and ethnic categories is necessary to determine whether conditions and care vary by race and ethnicity. Epidemiologists also defend the use of racial and ethnic categories to understand contributors to disease such as the stress of experiencing racial prejudice and reduced access to care because of bias.