The point about the "straight white male" was about how minorities and women are paid less. (I haven't seen any data about straightness). However, I have no idea how well that statistic normalizes the data for position/education/experience/etc.
I will say that studies have demonstrated that starting out is often harder for minorities, and therefore it is harder for them every step of the way (because if you are always moving one rung up at the same pace, but you started one rung back...)
But ultimately, that issue seems far easier to study if we had open salary data.
