Since the 1970s, the roles of women as both students and athletes have changed in higher education, with female enrollment surpassing male enrollment, and female athletic participation showing gains as well. These changes have generated public interest in whether women participate in athletics at comparable levels to men and whether men's opportunities have decreased as a result of the increased opportunities for women. Under the Comptroller General's authority, the Government Accountability Office (GAO) assessed the extent to which the numbers of men's and women's intercollegiate sports teams and participants at 4-year colleges have changed from the 1991-1992 through 2004-2005 school years. GAO analyzed athletic data from the National Collegiate Athletic Association (NCAA) for two groups of colleges: (1) the entire NCAA membership, or open group, for which trends will reflect school-level decisions and membership changes, and (2) the consistent members of the NCAA throughout this period, or closed group, for which trends will reflect school-level decisions only. While the numbers of both men's and women's intercollegiate sports teams increased from 1991-1992 to 2004-2005, women's teams showed greater gains than men's teams. There have been more women's than men's teams since the mid-to-late 1990s for both the entire NCAA membership and the group of colleges that were consistent members of the NCAA throughout this period. For both groups of schools, most women's sports and some men's sports showed increases in teams, but many men's sports showed mixed or small changes in the number of teams. The numbers of both male and female athletic participants increased from 1991-1992 to 2004-2005--with female participants showing larger rates of increase--but men's participation levels were greater than women's throughout this time period, both in absolute terms and relative to their respective enrollments. Most women's sports and half of men's sports showed increases in the number of participants across both groups of schools. In the context of enrollment, female participation grew at a faster rate than female enrollment in both groups of schools. However, from 1991-1992 to 2004-2005, overall participation rates were significantly greater for men in at least three out of four coed schools in the closed group. Appended are: (1) Briefing Slides: (2) Scope and Methodology; (3) Schools Included in the Open Group; (4) Schools Included in the Closed Group; (5) Comments from the Department of Education and (6) GAO Contract and Staff Acknowledgments. (Contains 9 figures, 4 tables and 12 footnotes.) [This document was produced by the U.S. Government Accountability Office.]