Second, I went to MIT for computer science. I TA'd a bunch of classes. There were quite a few students who were barely scraping by, and they were mostly men. This might be politically incorrect to say, but it's true. The fact that you see 60/40 enrollment ratios at MIT doesn't mean that MIT has 1.5 times as many qualified men as women in course 6.
The National Girls Collaborative Project said that woman received 57% of all bachelors degrees but only 18% of computer science degrees http://ngcproject.org/statistics further some sources say the ultimate percentage of female software developers is even lower, as low as 8%.
Women are succeeding at school but they aren't going into computer science and a greater percentage of them are leaving.
Your belief that there are just as many female developers as men is utterly unfounded and without merit.
The fact that you interact with a lot of female developers doesn't change the actual numbers and the plural of anecdote isn't data.
We have one side complaining that we need to erase the gender gap in computer science, another scoffing and saying girls just don't like computers. It probably doesn't help either case to pretend that there is no gap.
If you're looking at current ratios only, then you're ignoring the past ratios over the last, say, 20-30 years which would have been significantly more male-dominated.
I don't think there is any evidence supporting the assertion that more male applicants = more unqualified applicants.
That's an assumption, and not the assumption I'm starting from. I think that your pool of 75% men and 25% women does, in fact, contain n/2 qualified men and (75% - n/2) unqualified men, and n/2 qualified women and (25% - n/2) unqualified women - that is, the number of qualified men and women is the same, but there are far more unqualified men in the pool. If your recruiting process has false positives (and everyone's does), you'll end up hiring much more unqualified men than unqualified women, as a result.
Mine is also an assumption, but it seems to line up better with the underlying null-hypothesis that, in the abstract, the same number of qualified men and women exist in the world.