In this position paper, the American College of Physicians (ACP) examines the challenges women face in the U.S. health care system across their lifespans, including access to care; sex- and gender-specific health issues; variation in health outcomes compared with men; underrepresentation in research studies; and public policies that affect women, their families, and society. ACP puts forward several recommendations focused on policies that will improve the health outcomes of women and ensure a health care system that supports the needs of women and their families over the course of their lifespans.