I think both a mother and father can both work while their child is either in day care or in school, I don't think it's necessary for one parent to have to be home with the child, the majority of families can't financially support themselves without both parents working full time.
No, working mothers do not need stay-at-home dads. Children should, however, be given proper time and attention by their parents. A stay-at-home dad might be a great solution, but if it isn't possible, the parents should do everything they can to take responsibility and provide for their children both physically and emotionally.
No, I think a mother should have to work only when the dad is not making enough to make ends meet, because real men are supposed to work, otherwise they will get depressed. It would be unnatural for a man to take care of the kids whilst the mother went to work.
It is my opinion that working mothers do not need stay at home dads in order to hold down a full-time or part-time job. Both parents should ideally coordinate their professional schedules so that they each have enough time to spend with their children, and doing what they need to do for their work.