Addendum: to be clear, I'm calling "parenting and child-rearing in general" a field of expertise, not just knowing how far a child of a given age can walk!
And yes, I am *damned well* calling parenting and child-rearing "expertise" or "expert knowledge". At least for some people. I know there are those who do it very badly, but there are also those who do this incredibly hard thing very well, and to them: 🫡 3/2