Do women earn less than men? I think the empirical evidence would say yes, on a whole. But it is my firm belief that you have have a man and a woman who are equal in all respects of education, experience, age, time in service, etc., that is all the factors that are accounted for when determining pay, you don't have pay difference. The problem is that when looking at the pay gap, researchers rarely find such a siutation in a large enough sample and so they have to control for things like, age, education, experience, years in the workforce and that whole pesky personal choice thing. The lesson from this post is to read carefully everything you cite to, because it may come back to haunt your conclusions.