Physicians make subjective visual assessments concerning the race and/or ethnicity of their patients and document these assessments in patient histories every day. Medical students learn this practice through textbooks and the example set by their educators. Although physicians may believe that they are helping their patients, the practice of using visual clues concerning race and/or ethnicity to determine whether a patient is at risk of certain diseases lacks scientific rigor and may put the patient at significant risk of receiving substandard medical care. The authors argue that if the patient's race or ethnicity is of critical importance, the data should be collected through more objective, scientifically rigorous means, such as genetic testing. In this article, the authors call for the widespread transformation of the way medical schools teach tomorrow's physicians about the role of race and ethnicity in taking medical histories, and they challenge physicians to change their current practices.