If mom goes to work and dad stays home with the kids, mom is still the "designated parent," despite the fact that dad likely handles all of the day-to-day little stuff of parenting. This is insulting to dad, who likely is more in tune with who likes to eat what at a given time, what the newest favorite habits are, and what will trigger or diffuse a tantrum.
Furthermore, dad's care of the kids while mom is at work is considered a "childcare arrangement." You know, like daycare or school would be reported. Okay, fair enough. But when dad works and mom stays home? Is that a childcare arrangement? Nope. Apparently that's just what's expected to happen. Despite the fact that most women had a job or career before staying home with the kids, mom's care of children is not a "childcare arrangement." Insulting to mom, as her parenting isn't even reported, despite the fact that it is in reality a "childcare arrangement" (I doubt most women would be sitting at home not working if they didn't have kids to mind). Insulting to dad, as his parenting is considered unequal to that of mom's, and could be considered "babysitting" according to the U.S. Census Bureau.
From K J Dell'Antonia:
That bears repeating. If, every morning, I go off to work and my husband stays home with a child, that’s a “child care arrangement” in the eyes of this governmental institution. If the reverse is true, it’s not. I asked Ms. Laughlin if the Census Bureau collected data on the hours mothers spend offering “work support” to their husbands. “No,” she said. “We don’t report it in that direction.”If we are to ever change the way that businesses and governments look at parents, families, and their relationship to the workplace, we need to at least collect statistics in a manner that reflects our modern reality. We need to purge these 1950's-era ideas about what a family is "supposed" to be.