According to this graph of Canadian medical school enrollment, men outnumbered women by three to one in 1970. Women finally reached parity in 1995. By 2005, women made up nearly 60% of students in Canadian medical schools. At one, McMaster, women constituted over 76% of the incoming class of 2002.
McMaster eventually determined that the imbalance was not healthy and decided to offer a kind of affirmative action for male applicants. By reducing the emphasis on GPA and broadening the criteria for admission, they were able to offer spots to more male students.
I think of this disparity, too, in the faculty development events we organize. Participation in seminars and mentoring programs is overwhelmingly female. This could reflect the preponderance of women at the lower ranks of the faculty, the target audience for many of our activities. Or it could be that women are more sympathetic to the kind of professional education that we offer.
Of course, even to worry about having too many women is unfair because no one seemed to mind when men dominated medical campuses. But we do have an interest in producing both male and female doctors and scientists and making everyone feel welcome at our events.