Some heartening research:

"The committee also reviewed information about patterns of doctorates awarded to women and to individuals from racial/ethnic minority groups relative to the 'scholarly quality of program faculty.' Overall, the committee found essentially no relationship between 'quality' and patterns of enrollment and degree attainment for women. Although top-rated programs in most fields enroll and graduate many more students on average than lower-rated programs, women tend to be represented in the same percentages across quality groupings within a field. An exception appears to be certain subfields of Engineering in which top-rated programs are slightly more likely than lower-rated programs to enroll and graduate women. However, the total fraction of women remains quite low in those fields in comparison to other fields included in this study. "

Research-Doctorate Programs in the United States: Continuity and Change (1995)