NPR has a short piece and a new podcast up on Planet Money in which they try to answer the question of why the fraction of women going into computer science has been declining almost continuously since peaking in 1984. Their answer is twofold: (1) home computers were marketed first and foremost as toys for boys during the first major wave of consumer uptake, which in turn effected the skill-sets that young men and women brought with them to college, and (2) geek culture, as portrayed by mainstream culture, has always been fairly male-centric, with few exceptions.
Personally, my theory is that computers emit less of an estrogen vibe. What’s yours?