When a guy with a salary marries a woman with a salary, their joint income together is taxed at a higher rate than when they were not married, and paying taxes as two separate individuals.
This discourages legal marrying. That's bad. It COSTS them money to marry. Bad.
This also discourages wives from working. The same money if made by only one spouse, not two, is taxed less than if it were made by both spouses. That part is good for childbearing. But. However.
It impacts less affluent couples harder, because it is harder for less affluent men to do without their wives' salary. In that way, the marriage penalty is a kind of gift from the lower class to the upper one. Regressive.
What marriage penalty?
When a guy with a salary marries a woman with a salary, their joint income together is taxed at a higher rate than when they were not married, and paying taxes as two separate individuals.
This discourages legal marrying. That's bad. It COSTS them money to marry. Bad.
This also discourages wives from working. The same money if made by only one spouse, not two, is taxed less than if it were made by both spouses. That part is good for childbearing. But. However.
It impacts less affluent couples harder, because it is harder for less affluent men to do without their wives' salary. In that way, the marriage penalty is a kind of gift from the lower class to the upper one. Regressive.
Here is a discussion of this:
https://www.cpajournal.com/2019/02/04/the-status-of-the-marriage-penalty-an-update-from-the-tax-cuts-and-jobs-act/
Why can't you married file separately?
My wife doesn't work so I don't have this problem.