At my office, it is mostly men. I actually don't think I have ever seen another woman at the bike rack. I usually see a few women when I pass by downtown. I would love to see more women commuters.
I do ride kind of a girly bike now (Breezer), but more due to my back injury than the fact that I want to look delicate. My commute is 14 miles one way, so I sometimes do the bike/bus combo. It's just sad becuase I know several women in my office who live much closer than me but wouldn't even consider riding.