OF COURSE: "You know that “women make 77 cents to every man’s dollar” line you’ve heard a hundred times? It’s not true." Read the piece. It doesn't have the ultimate explanation, though.
If companies really 30% less to women for the exact same job, there would be hardly any man working. Because, didn't we agree that corporations are evil because they only care about money? If so, why throw 30% of your labor cost out the window?