The discussion started with one simple stat: only 4% of Summer of Code participants are women. Comments suggest that the numbers for open source software in general are even worse and that, although not ideal, the field of computer science in general does seem to be doing somewhat better. The question posed was simply this: why are women interested in development shying away from open source in particular?
My first thought on this was that women tend to appreciate social contact. And I'm going to guess that this means face to face, bona fide real-life interaction, not just the virtual variety. There seem to be relatively few opportunities to meet other members of an open source project's community other than the occasional conference. Would most women enjoy working with people they've never met, knowing only their online personalities?
A timely technology news update from ACM included an article about why there aren't more women working in high-tech in general. Sadly, I can't find the article now, but the main point was that many women are turned off by the working environments found in most high tech places. With open source development largely happening online only, it goes without saying that there isn't much of an 'environment' at all. No lunches with coworkers, no fun days, and no jokes during team meetings. It is also possible that the virtual environment created by the community would be suitable, but that women aren't able connect to their fellow developers in a meaningful enough fashion to discover this. This comes back to the whole social contact thing.
Finally, ask yourself which gender is more likely to come home after a long day of work (possibly of coding) and fire up the laptop to scratch that burning itch by working on some project that doesn't result in any kind of financial gain. You're picturing a guy, aren't you? Even women without families seem to enjoy taking on activities that have nothing to do with work during the evenings and weekends. It's not that they didn't enjoy the programming they did during the day; it's just that there are so many other things to get done after the steam whistle has sounded.
I know I can relate to each of these three issues myself. I definitely appreciate the social aspects of a regular job. I always look forward to fun days out of the office, and getting together with coworkers over lunch. Heck, I even enjoy meetings because of the opportunity to interact with others! I have found that even regular high-tech companies can often fail to satisfy my social needs - too many employees don't tend to want to do anything except work on their piece of the project. And yes, these tend to be the males!
Having said that, however, I can also say that I can enjoy working on my own as well. So far, I don't mind the 'reclusiveness' of open source too much; I guess we'll have to see what my feelings are at the end of an entire summer of doing it. I can absolutely see myself contributing beyond the Summer of Code, but I could never put in the huge amounts of time into open source (or any coding project) that I see some guys doing. After all, I have to save time for laundry, gardening, motorcycling, taekwondo, yoga, snowboarding, ...