An analysis by Jason Sheltzer, a graduate student in cancer genomics at the Massachusetts Institute of Technology, and Joan Smith, a software engineer at Twitter, have published a study that shows that male faculty members at high-ranking biomedical research institutions employ fewer women as graduate assistants and postdoctoral fellows than women faculty members. Furthermore, male faculty members who are the most elite in their fields employ even fewer women than male faculty members generally. (Elite faculty are defined in the study as being members of the National Academy of Sciences, being an investigator for the Howard Hughes Medical Institute, or winners of major career awards.)
Graduate assistants and postdocs in the laboratories of elite scientists are the most likely to be hired to tenure-track faculty posts. So a bias against women in these graduate assistant or postdoc positions, may be having an impact in the number of women hired to faculty jobs in STEM fields.
The paper, “Elite Male Faculty in the Life Sciences Employ Fewer Women,” was published in the Proceedings of the National Academy of Sciences. It may be downloaded here.