Never have children, only grandchildren.

Vidal’s quip plays on a familiar comic “grandparent’s privilege” idea: grandchildren are enjoyed without the daily burdens of raising children. The line suggests that the pleasures of family—affection, continuity, amusement—are separable from the responsibilities, sacrifices, and anxieties of parenthood. In Vidal’s typically sardonic style, it also reads as a critique of social expectations that equate adulthood with having children, implying that the institution of childrearing can be more obligation than fulfillment. The joke’s sting comes from its impossible advice (you can’t have grandchildren without children), underscoring the tension between desire for legacy and aversion to domestic duty.