In 1978 a young woman named Maria Klawe arrived at the University of Toronto to pursue a doctorate in computer science. She had never used a computer—much less written a line of code—but she had a PhD in math and a drive to succeed in a male-dominated field. She was so good that, nine months later, the university asked her to be a professor. Today, however, computer science is one of the few STEM fields in which the number of women has been steadily decreasing since the ’80s.