In the past decade, the reduction of health disparities has become an important policy agenda in the United States. Clinicians in practice, however, may be unfamiliar with the prevailing causal theories and uncertain about what they can do to help to reduce inequalities in health. The purpose of this article is to provide women's health care clinicians with an overview of the definitions, measurement issues, and theories that fall under the rubric of health disparities. The intersecting roles of genetics, race/ethnicity, environment, and gender are discussed. The article also provides practical suggestions for interventions and health policy change that can be implemented by clinicians in practice.