How to foster gender diversity as an organizer I am part of the organizing committee for a workshop in a STEM field that historically has problems with underrepresentation of women (and other groups, but let me focus on women in this question). I would like to help foster an inclusive environment at the workshop and more generally in my department and am looking for suggestions for how to proceed. 

The topic of the workshop is slightly out of my field of expertise and I do not have a long list of qualified speakers (of any gender) that I can offer suggestions from. 

I suspect that the senior member of the committee will take the attitude that he is "gender blind" and chooses speakers to invite based only on their quality but that because of implicit biases, the invitee list he draws up will be something like 90% male. I do not think he will be particularly open to a direct conversation about gender and underrepresentation.

I saw this question which was asking whether preferential invitation of female speakers is normal; I am instead asking how to foster diversity (perhaps by preferential invitation or by other means).
Aimed at a different point in the pipeline, you can try to make it more possible for speakers to accept your invitation. One step that can make a huge difference for certain people (in many cases, converting a 100% impossibility into an acceptance) is to provide resources for childcare at or near the conference.

For some ideas about specific steps you can take, Matilde Lalin recently wrote a nice overview of different ways conferences can and do support attendees traveling with children (published on Terry Tao's blog).

One that's not mentioned there is to allow attendees to purchase a hotel room in the conference-reserved block for a nanny. I know that the American Institute of Mathematics does this, and it can make the difference if the only other option would put the nanny somewhere far from the conference. 

Depending on the size of your conference, this needn't necessarily mean that you subsidize or even organize the childcare; it can help even just to put attendees in touch with local daycares/nannies/babysitters, or provide other information. However unless your conference is very small, I hope you'll give thought to implementing some of the other steps that Lalin outlines.



Added February 2015:

Greg Martin has written an excellent paper "Addressing the underrepresentation of women in mathematics conferences" that addresses exactly this question, which is simultaneously scholarly and actionable. In particular, in Section 4 (pp 17-21) he gives thirty-eight concrete suggestions that organizers can follow. Not all of them will be applicable in a given situation (including that of the original question here), but many will be.