Comment by solipsist

  Perhaps women just don't want to get into computer science.
  And no amount of bending over backwards and trying to
  appeal to female programmers will get us to a situation of
  50% female developers.

Or perhaps they do want to get into computer science and there are a number of obstacles stopping them. Most people would agree with this.

If you're going come up a controversial answer, you better have some solid evidence backing you up.