One fascinating aspect of this is how bad the post 1990 startup culture has been for women. There was something about those big, boring corporations of the 1970s and 1980s that actually gave female hackers more acceptance than what startups have offered.

You can see female interest in programming change in the charts on these pages:

http://blogs.computerworld.com/it-careers/21993/women-comput...

Note that those graphs show raw numbers, not a percentage of the population -- if you adjust for the growing population, female graduation rates in computer science peak in the 1980s. As it says in the text:

"As a share of all CS bachelor's degrees granted that year, females had slipped almost 10 points, from 37% in 1984/1985 to 27% in 2003."

A family anecdote: my mom was working on her Phd in urban planning back in the 1970s and her advisor said to her "You know, in the future, many of these issues of traffic and resource allocation will be resolved through computer simulations, so you should learn to program." My mom thought that was a good idea so she took some classes and learned basic programming. She does not recall feeling like an outsider in those classes: the computer field was still new and felt wide open.

Nowadays a lot of startups talk about the need for "culture fit". This tends to limit the diversity of the gender and race and class of who is hired. For contrast, consider people like Evelyn Boyd Granville, and her acceptance at IBM.

http://en.wikipedia.org/wiki/Evelyn_Boyd_Granville

Here on Hacker News we also discussed the story that Raganwald posted, about another black woman at IBM, though that article is now offline:

http://raganwald.posterous.com/a-womans-story

If IBM applied a filter of "culture fit" then these women would not have been hired. But IBM, and many of the big corporations in the USA, followed very liberal policies that promoted diversity in the work place.

There were some startups from the 1950s and 1960s that broke new ground in terms of diversity. Ray Kroc built up a small startup called McDonalds and in a quiet way he made feminist history in his treatment of June Martino. She was initially hired as the bookkeeper, but she was later entrusted with vast responsibilities and finally, in 1965, when McDonalds went public, she was given shares in the company, exactly like any other cofounder of a startup. This was apparently the first time in history that a woman was treated as a real cofounder and given stock.

http://en.wikipedia.org/wiki/June_Martino

If you look at the numbers, it seems clear that the emergence of the tech-based startup scene, in the 1990s, changed things for women. The startups have not emphasized hiring diversity. The startups tend to emphasize culture fit, and they were doing so even before that phrase came into existence. Why this should be, I am not sure. There have been startups in the past that have emphasized diversity in hiring, so I am not clear why the current generation of startups cannot do so. But what is clear is that it is not a priority for them. The big and boring corporations of the past did a better job of creating spaces for women in tech.

Edit to add: to avoid being overly innocent, we should note how much the talk of "culture" is sometimes a smokescreen to hide power dynamics. Shanley Kane said "In Silicon Valley, and the tech industry in general, a lot of people were giving these talks about what their culture was and it was really superficial and focused on the privileged aspects of the company like free food and massages." Here on Hacker News we have already discussed the post "Google's 'free food' is not free" but it is worth remembering how much the talk about "culture" is just a negotiating tactic.

http://rachelbythebay.com/w/2012/01/21/notfree/