In order for human society to continue, mainstream families need to have 3 children. For a woman to have 3 children and breastfeed them for at least one year each, it only makes sense to be a stay-at-home mom. Raising children is the most important and honorable job of all, it is the foundation of our civilization. Without the hard work of moms having and raising good children, society will cease to exist in the future.
For people to think staying home to raise children is "an outcast, a domestic helper, or an invalid in a sense", is really a very short-sighted and uneducated opinion.