Medical schools and law schools used to be dominated by men. So did undergraduate majors in computer science and the physical sciences. As women started attending college in greater numbers in the 1970s, that started to change. Those gains have continued — except in computer science, where they've plunged, as you can see in this fascinating chart from NPR's Planet Money:
What happened in the mid-1980s? You should listen to the podcast for the full story, but the short answer is that as computers first moved into the home, they were mostly seen as toys — and those toys were marketed to boys and men.
The same kind of gendered marketing shaped the video game world. Polygon last year explored how the early gaming industry created gender-neutral games, or even games with female lead characters. But beginning with Nintendo, video games were were marketed as toys for boys. A similar dynamic appears to have altered the field of computer science.