Intellectual capacity- programming requires a certain ability towards abstract thinking and logic that a minority of the population is comfortable with.
I actually believe a greater percentage of the population, by far, is CAPABLE of this, but very few choose a path that gives them a self idealization that they believe they can or want to be a computer expert of any sort.
I'd argue that the skill-set to be an effective teacher is also not prevalent in the general population. This includes not only intellectual capacity (effective pedagogy is hardly a cakewalk) but also the emotional intelligence required to manage a classroom.
I think it gets back to self-image. Many many women can 'see' themselves as a teacher. Relatively few imagine themselves in a career in tech.
This is very much a cultural issue- the messages women receive from their media sources rarely contain reinforcement towards technical excellence.
This is a frustration for technically oriented men, I believe, because we aren't directly the source of this disparity- I think the vast majority of STEMish career men would welcome more women into the fold as true peers, but are somewhat aggravated by messages that we are somehow directly responsible for large cultural forces we have little/no power over.
Its been positive to see more girls get into sports as that message has permeated into the culture. Hopeful an equivalent message about women and STEM will percolate into the larger collective id.
I actually believe a greater percentage of the population, by far, is CAPABLE of this, but very few choose a path that gives them a self idealization that they believe they can or want to be a computer expert of any sort.