Who of us is mature enough for offspring before the offspring themselves arrive? The value of marriage is not that adults produce children but that children produce adults.

De Vries turns a conventional assumption about marriage and parenthood upside down. Instead of treating adulthood as a prerequisite for having children, he suggests that the experience of raising children is what finishes (or at least deepens) adulthood—forcing responsibility, patience, self-knowledge, and a reordering of priorities. The first sentence frames parental readiness as an illusion: no one is fully prepared until the reality of a child arrives. The second sentence broadens the point into a social critique, implying that marriage’s formative power lies less in producing offspring than in producing mature character in the parents. The wit carries a serious claim about growth through obligation.