The phrase 'women's health research' embraces women as part of the biomedical research engine while categorizing women as separate. Before personalized medicine can become a reality, we must first ensure that basic physiological differences between the sexes are clearly delineated. In this article we argue that research into sex differences should be encouraged at the most fundamental levels of the biomedical sciences. Moreover, appropriate representation of both sexes as participants in clinical studies is still critically needed. Academic and governmental organizations must continue to articulate strong policy in order to ensure inclusion and analysis of sex as a critical variable. Focused attention on sex as a contributing factor to health, disease and therapeutic activity will increase our fund of knowledge regarding our everyday health, increase the pace of clinical research and ensure a healthier population.