From NPR:

When Women Stopped Coding

by STEVE HENN

October 21, 2014 8:54 AM ET Modern computer science is dominated by men. But it hasn’t always been this way. A lot of computing pioneers — the people who programmed the first digital computers — were women. And for decades, the number of women studying computer science was growing faster than the number of men. But in 1984, something changed. The percentage of women in computer science flattened, and then plunged, even as the share of women in other technical and professional fields kept rising. What happened? We spent the last few weeks trying to answer this question, and there’s no clear, single answer. But here’s a good starting place: The share of women in computer science started falling at roughly the same moment when personal computers started showing up in U.S. homes in significant numbers.

I.e., about the time when computing stopped being a career, it started being an adventure. Before the personal computer came along, computers were most famously associated with IBM. IBM was the most valuable company on the New York Stock Exchange for much of the 1960s and represented extreme respectability (with a certain muted sexy Mad Men glamor):

Part of IBM’s shtick had been that it shied away from the kind of Disruption Hype we’re used to hearing from the computer industry today. Instead, IBM presented its computers as a reassuring part of the evolution of office machines, such as its old keypunch machines and its superb electric typewriter beloved by secretaries everywhere. (Possession of an IBM Selectric was a status symbol among secretaries when I started working in offices in the 1970s.)

IBM emphasized how anti-Disruptive its computers were: it put tremendous efforts into making business computers as painless to adopt as possible for large corporations. They were immensely expensive for what they did, but IBM tried very hard to make them not scary. Not surprisingly, women had a not insignificant role in this latest version of Office Work.

Tom Watson Sr., the famous CEO of IBM, recognized that women made up a huge fraction of office workers. From an IBM promotional document:

By 1953, IBM had enacted an unequalled string of progressive workplace programs and policies, from hiring the disabled in 1914, to the arrival of professional women and equal pay for equal work in 1935, to appointing the company’s first female vice president, Ruth Leach Amonette, in 1943. Amonette was one of the first executives, male or female, to publicly state the business case for diversity. Upon her appointment she asked, rhetorically, “Doesn’t it make sense to employ people who are similar to your customers?”

A case study: In the fall of 1984, the late Dr. Gerry Eskin, the vice-chairman of the market research company where I worked, gave me his PC XT and I immediately went nuts over the potential of the PC. I worked full time on introducing PCs to the company from 1986 to mid-1988. My nemesis during this era was D., the woman in charge of the huge staff that ran the mainframe, who hated microcomputers.

Back to NPR:

These early personal computers weren’t much more than toys. You could play pong or simple shooting games, maybe do some word processing. And these toys were marketed almost entirely to men and boys.

This idea that computers are for boys became a narrative. It became the story we told ourselves about the computing revolution. It helped define who geeks were and it created techie culture. Movies like Weird Science, Revenge of the Nerds, and War Games all came out in the ’80s. And the plot summaries are almost interchangeable: awkward geek boy genius uses tech savvy to triumph over adversity and win the girl.

So, it’s like Society then engaged in a Giant Conspiracy to undermine the Rousseauan paradise of the gender equal computing industry before The Evil Woz came along and ruined everything by inventing the personal computer.

In reality, however, the IBM Era had been a giant conspiracy by IBM to make computers as non-disruptive as possible. Before the PC, computing was the most famously well-organized and decorous career-path in America. The PC liberated the male sex to finally do what a lot of guys had been itching to do for hundreds of thousands of years: not shower, stay up all night, and obsess over something in which human emotions and codes of polite manners played no role.