The live-in nanny. A high-paid lawyer and a sr software engineer together make, let's presume they make $500k/yr combined. They should take some of that money and hire someone else to do it for them. The question shouldn't be to compare one mom's job vs taking care of two children, there should be a team of professional adults taking care of a cadre of children. Amortized over that, the numbers look a bit better.