When Joanne Atlee was an undergraduate student in computer science, more than a third of her class was made up of women. In graduate school, those ranks began to thin out, a decline that has continued through much of her career as a professor at the University of Waterloo.

“All of a sudden I am an instructor at Waterloo and 10 per cent of the class is female and it’s ‘Oh no, what happened?’”

The decline was country-wide. According to Statistics Canada, in the early 1990s, women made up about 30 per cent of students enrolled in computer-science and math programs. That number has slid steadily down since and is now stagnating at about 25 per cent – a drop that predated the 2002 dot-com bust – and which runs contrary to women’s rising enrollment in other STEM fields, including engineering.