I teach open source (among other things) at Portland State University. 20-30% of the students I've worked closely on open source projects with over the last five years are women---around 2-3 of about 10-15 per year. Of those, as near as I can remember about a third prefer emacs and about two-thirds vi. The ratio among my male students seems the same.
If you want to meet female open source developers who use emacs, I guess you're welcome to drop by and say "hi" to some. But it would be kinda weird---I guess you could give a talk in one of my classes or something and chat with them afterward. You can also meet married open source developers with kids who use emacs, and 40-something open source developers who use vi, and an up-and-coming young open source developer who prefers nano, and any number of other combinations of demographic and editor choice with varying likelihoods...
Here's a blog from one of my students, a woman who develops open tech and (IIRC) uses emacs: http://dotfiveone.com . Her current entry is about a bunch of women, one of them another of my students, who spoke at our recent open source conference in Portland. It's pretty likely some of them use emacs too.