A.S. Byatt in The Children’s Book (2009) answers:
The parents […] found it hard in practice to do what they believed in theory they should do, which was to love all the children equally. A man and a woman with nine or ten, or twelve children spread their love differently from the way in which they might have concentrated on a singleton or two infants. Love depended on the spaces between infants, on the health of the parents, on death, on the chances of which child survived an epidemic or an accident, and which did not. These were families in which the best-loved child had died, and remained the best-loved. There were families in which, apparently, the dead had disappeared without trace, and were not spoken of as realities. There were families in which an unborn child was dreaded and shrunken from, only to become, on emerging alive from blood and danger, the best-loved after all.Β -pp. 29-30
Later:
The young desired to be free of the adults, and at the same time were prepared to resent any hint that the adults might desire to be free of them. -p. 227
More from this book.