I mean, I'll spontaneously zero in on that one argument: suppose people of race/gender x are known to make less money in a given career than people of another gender/race. Does that really explain why there would be less of those people in the given profession? Seems to me that for that to be true, there would have to be other professions where the disadvantaged people would earn more.
Is that really the case for IT? As a black(?) guy, are there other (legal) professions where you are likely to make more money than if you would go into IT? Presumably discrimination would range across all jobs (even white garbage men might make more money than black garbage men), so it should be cancelled out as a reason for choosing a career.
Sorry if I don't understand you, but when I got my first computer I was 12. I really wasn't thinking about my career. All I knew was that I liked computer games and that it was cool that I could make the computer do things (actually make things appear on the TV). How would your gender or race change your reaction in the same situation? I really don't get it. And by the way, at the time the computer games of the day were Pong and Pacman, so nothing violent that would drive away girls.
Edit: sorry for my extreme examples (garbage men), I just like to use ridiculous examples to make things clear but often people take that the wrong way. I mean I use them for the sake of logic, not to offend.