Let me give another perspective. I'm from one of the developing (an optimistic term) countries mentioned.
While I was still in my home country, I worked in an IT consulting firm. My boss' boss was female, her boss (a VP) was female. A lot of the other bosses were female. More than half my teammates were female. 30% female / 70% male seems awfully low, it was more like 45%-55% female.
The company would occassionally send people to the US. Over time, over a hundred of us have moved here to the US. So you have a sample of men and women who are good at math and picked IT while they were in a country with few economic opportunities, and took them to a nation with financial stability - the two environments the article mentioned.
What's happened so far? In time, some of the women changed careers. Some went to medicine, going back to school in order to switch. Some went to completely non-science fields, like real estate. None of the men have switched careers.
I know some men still dabble in computers in their spare time - open source projects, linux, etc. None of the women do.
You have to put it in context then. It wasn't about speed, it was about who was willing to go further out on the water, knowing they had to have enough energy to swim back to shore.