My workplace is full of women who code, more than men, but to support their primary interest: neuroscience.
Just an observation. Most scientists I've ever met think they can code, but almost all of them produce terrible code that at best was up to par with a badly coded video game. See, its possible to hold biases against all sorts of different groups. In this case, its a highly educated group of both men and women from a wide swath of races. However, in my experience because of a combination of their own intelligence and their lack of a formal basis in programming combines to create someone who can't code their way out of a paper bag. Great neurosciencists probably but certainly terrible coders. Now, what does that mean for the topic at hand? It takes a great amount of dedication to become a really good programmer and perhaps women just don't want to go on a career path where they compete with a large amount of people who are willing to put in the time and effort to become really good at this esoteric profession.
Assuming that money is their only (or major) factor they use to determine what to major/focus upon in college is a projection others do. Perhaps if you could see the world through the eyes of a young women considering studying in CS, you might find that there are other factors at play here. Maybe programming, no matter how you dress it up isn't something most women want to spend their life doing? I don't know...but you don't either...