But, yes, I think that there is ample evidence that major players in the development of the tax laws knew about these biases and were glad for them, and it certainly keeps getting worse. And it did, enormously. For example, I learned that social security was revised in 1939 in a way that hurt married working women, and the framers of that law thought it was a good thing. As recently as 1980, for example, Pete Stark, a Democrat, suggested that if tax law had to help any kind of family, it should help single-earner ones, because jobs are scarce and the system should reward families where one spouse stays home. Very much so.
Tax is a very political subject.
That turns out to be a very sophisticated piece of political strategy designed to keep women in the home. That's a good question. I find, throughout my work, that I am interested in problems that affect real people as they try to better their lives. Those problems are necessarily interdisciplinary ones, because they didn't start in some academic laboratory or library. They started in the real world, and that's a multi-disciplinary place.