Computer science today is a male-dominated field. We know this. I’ve been meeting these women — women whose names we should know too — badass computing pioneers — women who are now in their 70s and 80s but who programmed some of the first digital computers back in the days when software was written in machine language — in binary. So how did women go from being the center of the computing world — the pioneers of the industry — to being sidelined? I think the answer lies somewhere in this graph. It’s a graph of the percentage of women studying computer science. And it compares those numbers to the numbers of women studying medicine and law and physical sciences — and you know the number of women in all these fields are all going up — but then, something big happens — something that changes the course of computer science. And what’s amazing about that is you can actually put your finger on the moment where this changed. It was 1984. There was no grand conspiracy in computer science that we uncovered. There was no sign on the door that said “girls keep out.” In 1984 you couldn’t succeed in a computer science program without having had a home computer. And this bled into the workforce. Even if you weren’t studying computer science but you wanted to work on it, you needed the experience of using one, of playing with one. Early home computers popped up in the places that were already the world of boys. [Commercial: “This morning, Brian Scott made a career decision. “He decided to be an astronaut. “His first giant step: learning to use an Apple.” Jane Margolis is an education researcher who’s now at UCLA. And she has a theory about this. Take this one student Jane interviewed named Lily: She was the one who was really into computers in high school. But even though she was the one who was really into computers, the computer was placed in her brother’s room. Once you have something like this happening, it reinforces itself. Computers are for boys. They are boy toys that boys use to do boy things. And this became a narrative, this story we told ourselves. Margolis had some idea about how this had happened. But she wanted to figure out how to stop the clock — how to reverse this — how to find a way to get women back in. Margolis did her research with a guy named Allan Fisher, who was the dean of computer science at Carnegie Mellon at the time. To give girls a chance to make up for what they missed in those years when boys were messing around with computers in their bedrooms, Carnegie Mellon added an intro course for students who didn’t have a lot of informal computer science experience. They started paying a lot more attention to teaching. And it worked! By 2000, 42 percent of the computer science students at Carnegie Mellon were women. And the dropout rate for men and women was basically the same.