My wife had a similar issue, except the other way around. She got paid a bit more than another person (male) who graduated at the same time and had the same amo

My wife had a similar issue, except the other way around. She got paid a bit more than another person (male) who graduated at the same time and had the same amount of experience. When I inquired I was told it was because she was a better negotiator and negotiated a higher salary. Don't get me wrong, I'm 100% for income equality opportunity. That is, on average, the same experience, education and job pay the same for both sexes, sexual orientations, races, religious and so on. But taking a single case and making a cause of it is difficult, since it is just a single case.