I am in complete agreement with Moss-Racusin that gender bias remains a barrier to women's participation in science. This problem was nicely demonstrated in her and her colleagues' paper (Moss-Racusin et al. 2012) and has also been shown previously (e.g., Wennerås and Wold 1997). My article was not meant to be an exhaustive survey of the various factors that impede women scientists. I wanted to focus on one critical issue that I think has been neglected—that is, that the oversupply of biologists disproportionately disadvantages women. It is this pressure that gives gender bias much of its bite. When competition is fierce, bias can be lethal.

As biologists, we know the power of the comparative approach. In this article, I was searching for the differences between medicine and science that might explain medicine's greater success at recruiting and retaining women. Women in medicine must also contend with gender bias (e.g., BMA 2004); this bias negatively affects the career trajectory of women physicians (Gartke and Dollin 2010). But it has not prevented the continued increase in the proportion of women in medicine (CMA 2010). To emulate medicine's success in attracting and retaining women, we will need to increase job security for trainees and make the competition for entry into our profession occur earlier in training. I believe that these are important features that help medicine recruit an increasing number of women.

Part of my motivation for writing this article was that our current system rewards the overproduction of biologists. For example, in the Canadian system, the Natural Sciences and Engineering Research Council of Canada awards one-third of an applicant's score for training students. No one would suggest that gender bias should be continued, but we seem unable or unwilling to discuss how our overproduction of biologists may reduce the participation of women in science. I hope the article might start this discussion.