Quick anecdote from an earlier time. My mother's college roommate (Marilyn) studied Math and Physics in undergrad in the late '50s/early '60s. She went on to do a Masters at MIT and worked on the Apollo project there, which by that time was being run by another woman: Margaret Hamilton.

If I remember the story correctly, Marilyn started a PhD, but never finished due to marriage and kids. She went on to have a very happy career at NASA and retired from there eventually, around 1995.

She worked in code for almost all of her career. She worked on the Apollo Guidance Computer for at least a couple of years.

Her telling of how things were is that there were a lot of women working in what would eventually become the field of computer science. It was a flipped version of what we think of now but with some similarities.

It was flipped because women were the higher percentage of the work force in the early '60s and on into the '70s and even '80s. But this was also the same as today because the field itself was really not well-defined, and after people went from punch cards (which is what she started programming with), they went to typing. And for the average Joe, typing was a job for women: it was secretary work.

So this seems to me--with the caveat that I'm remembering some conversations I've had with this women from maybe 10 years ago when I first got interested in software and started having jobs that involved it--that there was a brief opening window at the early stages of the field when there were a lot of women practitioners.

As the field became more mainstream and more codified and promised rewards and opportunities, it appears that the guys noticed and came in rather slowly. And then pretty suddenly when it became clear that you could make a quick buck without a crapton of advanced knowledge, the brogrammers showed up and pretty much took over.

That's obviously only one interpretation, but it's an interesting one to me because Marilyn retired before things seem to have got really bad. She retired when the women were still wearing dresses to work, and the men were wearing suits, and things were mostly professional. There were probably glass ceilings, but she didn't feel one in her work because NASA has an institutional history of women doing big, important things.

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Another anecdote. This one much shorter.
A second field that seems to be to being opened up by bro-ish types (and with the incompetence and general lack of knowledge and laziness I associate with that type) is healthcare--specifically Nursing.

When I was studying Statistics at the University of North Dakota, I was living in a house with 6 other guys. Two of whom were Nursing students. They would have frat-style parties several times a week. Parties where 35-40 of their nursing school guy friends would come over, play Nickelback all night long and drink shitty beer. Basically the opposite of what I would expect from Nursing students.

I found this pretty unexpected and asked once WTF was going on here.

The answer was pretty consistent: there's a dearth of Nurses. People will pay a lot for them. The barrier to entry is pretty low. Essentially, it's quick easy money.

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All this makes me wonder how much of the shift in industry demographics is really driven by institutional sexism and how much it is just that the lowest common denominator will always try to make easy, lazy money. And then the more competent people move elsewhere, or just leave the industry entirely and go do something else.

Of course, once you reach a critical mass of bro-ism, the institutional bias does become real. But I wonder if we have a situation in business or IT management that is somewhat akin to the problems we have in U.S. Politics: the only people interested in managing are, by definition, not fit for the job. So smart people give up and walk away to something else.

The other thing that it makes me wonder is this: how many other industries are there that started out with one traditional mix of demographics because "that's a job for x type of person. Not someone like me. And was then co-opted by the someones-like-me.

Anyway, sorry for a long musing. Just trying to put some puzzle pieces together here to see if there's a larger idea to digest.