I believe CaesarAugustus had such a tax on bachelors as a way to encourage families and producing more Romans. He called himself the restorer of the Republic and its traditions even though he was essentially setting up monarchy that took power from the assemblies and the Senate. .
In The Rise and Fall of the Third Reich, William Shirer, the author, wrote that Hitler actually said: "In the Third Reich, every German girl will be able to find a husband."
My Dad is a CPA and he told me that when you get married, the way the tax system is set up, you end up paying more, but when you factor in the tax credit it all evens out (don't ask me to explain it!), but you're right about the child credits.
