It's really quite funny too, because women were a huge population of programmers and computer science graduates all the way up to the mid 1980s, when the ratios began flipping in favor of men. The biological argument would assume that either something changed biologically from 1980s onwards to make women less predisposed to be programmers, or (the more usual argument I see) 'that they were just doing the gruntwork' which usually exposes them as who they are.