1) The social interaction leaves something to be desired at my job, especially if you are not into gaming or D&D. There are few coworkers with whom I can discuss non-geek topics such as travel or food. This is probably due, at least in part, to having so few women around. The guys constantly revel in their geekitude. It gets old.
2) The work itself is isolating. I love to code, but especially during the long, depressing months of winter, I long for meetings to go to, or phone calls to receive.
3) Similar to the last point: I'd like to have a reason to leave my desk several times a day, for periods longer than it takes to get a cup of coffee or go to the bathroom. The highly sedentary nature of the job starts to make it feel like a prison.
In contrast to the last couple of points, my male coworkers act as though they would be happy if they never had to leave their desk chair to go to another meeting. Maybe this is just personality, and not a gender difference. Maybe I don't love programming enough to lose myself in it for hours at a time. I think some of these things, however, especially the social issues, may be indicative of basic female needs to have a connection with others, a feeling of being nurtured (and nurturing others), and good (female) role models. It would be interesting to see a workplace in which the majority of developers are women.
I recall reading about a study recently in which they found that men tended to concentrate in the hard sciences (math, physics), where women preferred sciences with a human aspect (psychology, biology). I believe they found that even women who had entered the hard sciences often ended up leaving them for fields with a more human touch.