[BearsAreCool]

I think it is misleading to use the lowering rates of women in computer science as proof of anything, especially when you look back to the 60s or 70s. Unlike many scientific fields computer science was much more of a womans field when it started off than it is now, for instance (and I am aware this is quite possibly cherry picking) if you look at images of the bletchely park codebreakers who worked on the origial turing machines to break encryption you'll notice a majority are women. One explanation I found of why this changed in america was the marketting of console video games, up until around the 90s these were not sold as toys and when it came for atari and such to choose between marketting to boys or girls, they chose to sell to boys, leading to connections between boys and computers or electronics.

I don't think this has anything to do with how sexist america is at any time, but rather how the gender roles have changed over a relatively short time period.