If governments need to raise revenue, it is well known that the best thing they can do is through sin taxes, such as for carbon emissions in general, gas in particular, alcohol, tobacco or workalcoholism (or subsidize fitness). If this is not sufficient, the most inelastic goods should be taxed, i. e., goods whose quantity is little influenced by changes in its after tax price. In the context of labor income taxation, this means men should be taxed more than women. Indeed, the female labor supply is much more responsive to after tax wages, as men work anyway.
Alberto Alesina, Andrea Ichino and Loukas Karabarbounis expand on this idea, noting first that is common to discriminate by gender, say through affirmative action, different retirement policies or maternal leaves. So why not discriminate more efficiently through the price system instead of quotas? From an economic point of view, this seems obvious. But somehow this is not popular with the general public. Is it because the basic economic model is missing something?
Alesina, Ichino and Karabarbounis test the robustness of gender based taxation to all sort of bells and whistles, and its optimality remains. In particular, they assume that men and women have identical characteristics and preferences but for the fact that men have higher bargaining power at home and can thus avoid household chores by working in the market. As long as household chores are unbalanced, taxing men makes more sense and improves overall welfare.
That said, there is no reason to stop at gender. I have argued before that luck at birth should be taxed, such as for tall people. Others have made similar argument for beauty. In fact, the strongest argument for development aid can be made on the grounds that where you are born is not something you have earned, and one should share one's luck with unlucky ones. And your birth place certainly is inelastic.