[aianus]

My assertion is that women shied away from this sort of unpaid time-intensive work even when they were not subject to the disadvantages you outlined (childcare and lower income). The real reason, in my opinion, must be something else.

In response to your questions: there was a single offering of the course. All of the women I encouraged to enroll said they were uninterested due to the perceived difficulty and workload. This may or may not have been a cover due to other concerns ("am I good enough?", "I heard only boys take this course", etc.). To be clear, the vast majority of men in CS were also unwilling to enroll in this course because of the workload.

[techpeace]

Well, I would have to disagree with your assertion that the women were not subject to any disadvantages, even the ones I mentioned. To know that outright would require something bordering on omnipotence. But feel free to believe that it must have been "some other reason," rather than the myriad entrenched disadvantages that exist in both our society at large and this industry in particular.