Having lived in the San Francisco Bay Area all my life and gaming for 20 odd years of it, I have only played with one woman DM. I'm trying to dig through memories and come up with any others, but the closest is at DunDraCon about 2 years ago when one of our newer gamers, a woman, met a woman crying in the bathroom. Being who she is, she asked what was wrong, it was something about her boyfriend being a jerk. So our lady says, "Well hang with us girl!" So for 2 nights she stayed in the room with the guys, (our girl was staying with her boyfriend) and ran a game for the group. I missed the game, either being home at the time or doing something else, I don't remember.
The one woman who's run a game, Cathy, is good, but lacking rock solid knowledge of the rules. This wouldn't matter for some games but in her case she was running Fantasy Hero. This lead to horrible broken characters and items and frustrated me. Her story abilities however are strong.
I've played with I believe 3 women at a time in the group and I'd guess I've played with less the a dozen women...Cathy, Heidi, Amanda, Rebecca, Nazli, Min Jun, Lisa, Rat Woman, Nine Inch Nails Woman, Navy Wife, Biopsy Girl, I wish I could recall all their names right now. Biospy Girl I think was Becky or some derivation of that, and she met the DM through the hospital. They both had cancer and so I remember she showed up to a few games looking weak and wearing a baseball cap. Rat Woman had rats for pets. Nine Inch Nails Woman hit on me mentioning she had an extra ticket to see NIN, but I didn't realize she was hitting on me, probably because I wasn't attracted to her. Navy Wife isn't a wife anymore. I've also played with Lizard's wife and another woman, sorry I can't remember their names, no slight meant Lizard. It was at BenCon last year and Lizard was running a playtest session.
Then if you count the one live action game I played in, well, that would shoot the number above 2 dozen but I couldn't tell you any of their names.
Then there is a phenomenon I've seen only twice. I'm not sure if this is a thread hijack, but it seems appropriate and we are already 5/6 pages in.

Twice I've seen wives of DMing guys seem interested in the game, not what seems like the logical interest in spousal activities, but actually hanging around to watch or even try to participate. And the husband asks them to leave. I vaguely remember the first guy stated, "We've talked about this before" and the second guy said, "I can't DM straight when she's watching."
Any insight into this?
Edit: again added more woman gamers to list.