The researchers also found that the influence of professor gender was even starker for the set of students who were math whizzes when they entered the Academy (those with math SAT scores above 700). For these students, a female instructor eliminated the gender GPA gap entirely—and solely because high-performing women did well in their classes rather than because high-ability men underperformed.
What's more, having a male instructor didn't just affect female cadets' performance in their first-year classes—ramifications could be seen throughout their undergraduate careers. Not surprisingly, students who did well in their introductory science classes were more likely to go on to obtain science degrees (and presumably go on to science-related professions). Among high-math-SAT students—those most likely to be the ones to go on to obtain science degrees—the authors calculate that having a women-only roster of faculty would create gender parity among science majors.
What is it about a woman instructor that is so important for female pupils? It's unlikely to be simply the sense of empowerment of seeing that women can in fact make it in science. If that were the case, then having all female professors should help their female students catch up to the men and having all male professors should cause the male-female performance gap to widen. Yet the authors found that, while female students perform better on average in classes taught by female professors, there are some male professors under whom there's no achievement gap between male and female students (and also some female professors for whom the gender gap is as big as that of some of their male colleagues). So some men are very good at mentoring women, just not nearly enough of them.
What kind of man makes a good mentor? Is it because, as is sometimes suggested, men with daughters make good mentors, having developed greater empathy for the challenges faced by their female students? Or differences in teaching style? The authors unfortunately don't know much about the Academy's teaching staff, so for now the enormous impact of professor gender remains a bit of a black box.
Regardless of the underlying mechanism at work, the study has wide-ranging implications for what might be done to keep talented women on science career tracks. Most obviously, the findings provide further justification for affirmative action programs to promote women in the sciences, to break the cycle of talented women opting out of science because there are no women in science. At the same time, we might unravel the mystery of what makes people—men or women—better at mentoring their female protégés.
I posed the question of how to create gender equity in science to Stephanie Pfirman, a Barnard College environmental scientist and a member of a Columbia University initiative on women in the sciences. She pointed out that recruiting female mentors and making men into more women-friendly bosses and teachers are both efforts aimed at changing the environment faced by young women. While these are worthy objectives, she suggested developing coping mechanisms to deal with circumstances as they are—for example, realizing that getting an A- or even a B+ in an introductory course doesn't spell the end of your career as a scientist, as many high-achieving young women believe. Yet the results of this study suggest that just by helping more women to overcome the adversities they face in becoming scientists today, we will make science less of a man's world for the female scientists of tomorrow.