It depends if the mother has a home job, and if she works from her laptop, etc. In my opinion, I am a bit biased because it depends on the mothers situation. Looking after your children isn't a job, more of your responsibility, and you also don't get paid for it (Unless you get funds from the government).
They're not exactly providing for the household now are they? The working folk put a lot of effort to make their money and they sometimes even endure extreme hardship to do so. A stay at home mom is dependent on the wages of her husband because the reason she is in the house she is staying in is because her husband can afford it. She cooks the dinner, wears the clothes does the chores in the home that is bought with her husband's money. She is not contributing as a provider so she cannot claim to be working. Also taking care of your children is your responsibility as a human. If you want to get paid to take care of a child become a nanny not a mother.