There is no evidence that female programmers write any differently than male ones, but there is plenty of evidence that they are treated differently.
You are right in that there has been a push to get women into computer science. There has to be a pull from industry, too. The students should be taken just as seriously as any other, but that does not happen and nor is it likely anytime soon without a push from people inside the industry http://blogs.scientificamerica....
In other words, many women have left tech because they were treated like shit there and they decided they would no longer going to take that crap any longer. You can pretend that is not so and turn a blind eye to it. I don't know if it is a learned behavior or if there is something intrinsic in humans that causes this. All I can do is hope for the former.
You mention wartime and yes, women did get a big boost in careers to fill the void that working men left behind, see the Rosie the Riveter character. Once them men came back, the women were expected to leave the workforce, to leave their jobs that they were doing perfectly well, and get back to raising children. You might be somehow immune from social pressure, but it weighs heavily on most people.