As far as I have seen, women doing commercial programming are a pretty low percentage. Of the 90 people who started my Uni Computer science degree, only about 6 were women, and 3 dropped out after a few months to do physics. This was 1991, and (according to people I've worked with since) things may have only doubled over the next decade or so.
When it comes to the workplace, I've noticed there is normally one, or perhaps two (tops) women per programming department (normally around 10 in each department).
So yes, in my experience there are only a small amount of women in programming. And that definitely is reflected here over the years.
And yes, Raven is right, this question (along with how old are you, what is the best game, and join me in programming FF99) is right up there with most likely to annoy quickest.
Cheers
I am 99% probably lying in bed right now... so don't blame me for crappy typing