Lack of Female Authors in "Beautiful Code"

Shelley Powers has pointed out that only one of the contributors to Beautiful Code is female. It wasn’t for lack of trying: I contacted fifteen women last spring and summer asking them to write articles for us, and only one was able to make the time. In contrast, the uptake rate among the men I approached was 25%. I’d welcome suggestions about how to improve this the next time around. I’d also like to know how to get more material from people who aren’t reasonably fluent in English: we only have one in that category this time as well.