This study for the U.S. Marine Corps consisted of four tasks: (1) review the literature on the integration of women in ground combat and other physically demanding occupations, (2) conduct interviews with representatives of organizations that have integrated women into physically demanding occupations, (3) estimate the costs of potential initiatives to promote successful gender integration, and (4) develop an approach for monitoring implementation of gender integration of the infantry. RAND researchers present a historical overview of the integration of women into the U.S. military and explore the importance of cohesion and what influences it. The gender integration experiences of foreign militaries, as well as those of domestic police and fire departments, are examined for insights on effective policies. The potential one-time and recurring costs associated with integration are estimated as well. The report culminates in a summary of previous monitoring efforts and broad strategic monitoring issues, as well as recommendations to the Marine Corps for implementation.