The clearly out-of-culture requirements for Catholic marriage point out that the whole sanctity of marriage argument is ridiculous. Churches will not be forced to marry pairs of men or pairs of women any more than the Catholic church is forced to marry infertile couples.

There isn't an explicit legal protection for this category, but consider this scenario:

"No, you can't add her on to your insurance plan because you knew you were infertile at the time you got 'married' and you didn't get permission from the Bishop, so we don't consider you married."

Yeah, that's going to go over real well in court.