But then childhood as such really didn’t exist, or at least it wasn’t a recognizable concept, as historian Philippe Ariès documented; this, too, is a social invention. Children were viewed as small adults; apprenticed out to work at age five. It was only as families began getting smaller—birthrates declined steeply in the nineteenth century—that the emotional value of each child increased. Which is where we find the origin point for most of our current ideas about maternal fulfillment.

