Being anti discrimination started with not discriminating people for things they can't control. Race, gender, etc. Now we're moving into territory of not discriminating against optional things people choose (having children). This is a very significant change, IMO. I wonder how far it can be taken. I think there's a fair argument that since pregnancy only affects women then it counts as gender discrimination. However…
Some of these classes are protected in the United States as of the Civil rights acts of 1964 and 1968, as well as other federal laws from 1974 and 1978. (The protection of different religions is, of course, a founding principle of the United States. However, many people do not believe religion is a choice.)
The following webpage was helpful in assembling this list and includes a few amusing items such as membership in the Communist party (not protected in Nebraska) as well as having a degree in theology (protected in Oregon): http://www.ncsl.org/research/labor-and-employment/discrimina...