Problem sets and other deterrents for women

In “Problems with problem sets,” authors James Trefil and Sarah Swartz use the word “problem” to refer to the fact that about 20% of physicists are women. Would they also call it a problem that less than 10% of nurses, elementary school teachers, and secretaries are men? Would they consider it good news if the percentage of men in those fields were to increase? Would they suggest that part of the reason for the underrepresentation of men might be that coursework for those professions includes problems that assume knowledge more likely possessed by women?

Of course the authors would never say that. In fact, it seems perfectly reasonable to just say that men are less interested in those professions than women are. Likewise, is it not also reasonable to assume that women are, on average, simply less interested in physics than men are?

At one point, Trefil says he tries to “be encouraging to his female students.” As opposed to what? Not encouraging his male students? The entire article was sexist.