The number of applications to medical schools has been declining at a time when attention is beginning to focus on the potential need to expand the infrastructure of medical education to meet the nation's growing consumption of health care services. To gain an understanding of the dynamics affecting the availability of medical applicants, the author used data from several decades to study the transitions that occur throughout the process of education-from primary and secondary education to four-year colleges and, ultimately, to medical school application-from the standpoint of individuals' gender. (A companion article in this issue reports the findings of a parallel study from the standpoint of individuals' race and ethnicity.) A progressive erosion was found in the level of participation of men in postsecondary education over the past 25 years, and a parallel decline was observed in the percentage of baccalaureate men who sought further education at the doctoral level, including medicine. These dynamics have occurred aside rising levels of achievement of girls in early education, increasing numbers of women in four-year colleges, and high levels of interest among college women in medical education. But despite this peak of interest, women baccalaureates have displayed a low frequency of application to medical schools. Based on these observations and on population trends among 20 year olds, it is projected that the number of women applying to medical school will continue to increase, but only modestly, while the number of men who apply will remain relatively unchanged. The resulting growth will be sufficient to alleviate the recent paucity of medical school applications, but it will not be adequate for the needs that any significant expansion of medical school seats will create nor for the numbers of physicians that a predominantly female profession will require.