Noumena has posted a deep analysis of the reasons for resistance to moves toward gender equity in physics, theoretical math, engineering, computer science, economics, and philosophy.
Although I said yesterday that I believe that the majority of such resistance, at least in philosophy, is passive rather than overt, it is sometimes given expression. It comes up, particularly, in conversations about the Larry Summers controversy or discussions sparked by comments like John Tierney's last month that women simply prefer less analytic and conceptual work.
This blog as well as others (and the SWIP list) have been keeping track of the research that needs to be done in order to make a strong case that the underrepresentation of women in philosophy represents an injustice. That case has been made strongly in scientific disciplines, as science institutions (departments, universities, federal agencies) actively work (and succeed at!) correcting participation inequities.
One thing that we need in philosophy is good evidence that women are in fact underrepresented. We have this for undergraduate education, from the U.S. Dept. of Education. The data that we have for graduate education is on graduation rates by gender. Some have claimed that without figures on graduate school application and acceptance rates, though, the data is incomplete because we don't know if the pipeline leaks in decisions to go to graduate school or if it leaks during time enrolled in graduate school. (I would claim that these data are relevant to implementing an efficient solution given our discipline's limited financial resources, but are not relevant to establishing the existence of the problem.) Likewise, we have federal employment statistics which show that professorships are male dominated. That type of data could be improved by knowing more about job application rates (by gender), job acceptance rates, and the part-time labor pool. The APA has said that some of this missing information is being collected for the latest job cycle.
Something else we need is a clear understanding and explanation of the persistence of inequalities in our field. Noumena's analysis is clearly motivated by the practical (that is, the rhetorical as opposed to philosophical) problem of convincing the resistant that 1.) unequal gender representation is a problem; 2.) unequal gender representation is a problem that we collectively ought to take responsibility for; 3.) unequal gender representation is a problem that our institutions have a duty to address.
There are two hurdles to be overcome. One is in the nature of trying to overturn a status quo. Even passive resistance to change can be enough to quell it. The second is that the causes of gender inequality are very likely irrational.
When we look at other struggles for justice, there are strong forces working against rational persuasion. We might hope that this is not the case for philosophers--that philosophers are more likely to change their beliefs and practices based on reflective consideration of rational argument. Although that is perhaps too optimistic, it suggests another avenue for research--collecting and responding to the reasons that are given for failing to address our professions inequalities.