The safety and effectiveness of medical treatments can differ in men and women for many reasons related to different epidemiologic characteristics, physiology, and body size. In general, women have higher bleeding rates and procedural morbidity and mortality than men, which means that their risk/benefit ratios for many implanted medical devices can differ from men. Therefore, sex-specific safety and effectiveness data are necessary for informed patient decision making. In 2008, the US Food and Drug Administration (FDA) convened 2 workshops on this topic that included multiple stakeholders—patient groups, medical device industry representatives, academia, and government officials. In December 2011, the FDA released a draft guidance informed by these workshops, entitled “Evaluation of Sex Differences in Medical Device Clinical Studies.”1 This document discusses the underrepresentation of women in medical device clinical trials and provides recommendations for increasing enrollment of women and performing sex-specific analyses. A 90-day public comment period began on December 19, 2011.