“The unitive capacities of the spouses don't exist for nothing; they exist for motherhood and fatherhood. That is the matrix in which they develop, for children change us in a way we desperately need to be changed. They wake us up, they wet their diapers, they depend on us utterly. Willy-nilly, they knock us out of our selfish habits and force us to live sacrificially for others; they are the necessary and natural continuation of the shock to our selfishness which is initiated by matrimony itself.”