I'm going to quibble with this just a bit. (But it's more a matter of "right answer - different reason")Some countries also have a government paid maternity benefit - sometimes in addition to a salary continuation. I would consider that sort of maternity payment government social security and thus most likely tax exempt if you are in a country with a tax treaty with the US.
Paid Family and Medical Leave: An Issue Whose Time Has ComeA new report from the AEI-Brookings Working Group on Paid Family Leave highlights the benefits and costs of providing paid leave from the perspective of workers, businesses, and society.
There was disagreement in the group about the specific design of a paid leave policy, but the group unanimously agreed that some form of paid parental leave should be offered to help workers at the time of birth, adoption, or fostering of a child.
The report suggests a compromise plan for policymakers to consider. The compromise plan would provide eight weeks of gender-neutral paid parental leave, replace 70 percent of wages, and offer job protection. The policy would be fully funded by a combination of payroll taxes and savings elsewhere in the budget, with no increase in the deficit but also no adverse effects on low-income families.