I haven't been able to find any usable statistics but from my observation of cycle commuters men appear to out-number women by around 10:1
This is in a relatively bike friendly city, at least by North American standards (Vancouver Canada). In my office, a downtown mixed office building, there are no women commuters.
There are many more women cycling in road clubs at the weekend and lots of women committed to cycling groups and promoting cycling.
Is there any reason why women don't commute by bike and is there anything that can be done to boost the numbers?
(rephrased to make this a more useful question - rather than a friday afternoon thing)