I worked for a Canadian insurance company in the mid-sixties and there were roughly as many women as men in the IT department and at various hierarchical levels.
I also worked for a large Canadian bank from the 1970s until the early 2000s and again there were roughly as many women as men and again at various levels within the organization. The exception was the area working with personal computers. Somehow the assumption that women could not work with PCs became common, though not with any evidence. I think it was because the early personal computers were full of games and hence toys for boys.
I have a daughter with a Masters in Computer Science and a Ph.D. in Microbiology. She is not an exception, there are many women in STEM. The problem is that their skills are not recognized.