I really think that it's something that each couple should decide between themselves. If they agree that one of them should become a full-time mother or father, and the other goes to work, and both are happy with that arrangement and can afford it, then I can't see it as a bad thing.
I don't look down on full-time parents. Looking after the house and the kids is a worthwhile way to spend one's time. It doesn't suit everyone, of course, but some find fulfillment in it and that is fair enough.