Judith Shulevitz spells out the downsides to delayed parenthood. Among them:

A mother who is 35 when her child is born is more likely than not to have died by the time that child is 46. The one who is 45 may have bowed out of her child’s life when he’s 37. The odds are slightly worse for fathers: The 35-year-old new father can hope to live to see his child turn 42. The 45-year-old one has until the child is 33.

These numbers may sound humdrum, but even under the best scenarios, the death of a parent who had children late, not to mention the long period of decline that precedes it, will befall those daughters and sons when they still need their parents’ help—because, let’s face it, even grown-up children rely on their parents more than they used to. They need them for guidance at the start of their careers, and they could probably also use some extra cash for the rent or the cable bill, if their parents can swing it. "If you don’t have children till your forties, they won’t be launched until you’re in your sixties," Suzanne Bianchi, a sociologist who studies families, pointed out to me. In today’s bad economy, young people need education, then, if they can afford it, more education, and even internships. They may not go off the parental payroll until their mid- to late-twenties. Children also need their parents not to need them just when they’ve had children of their own.

Allison Benedikt shares her own experiences.