If nature had arranged that husbands and wives should have children alternatively, there would never be more than three in a family.

Housman’s quip hinges on a counterfactual: if men and women had to alternate the physical burden of pregnancy and childbirth, family size would shrink dramatically. The joke depends on a widely recognized asymmetry—women bear the bodily risk, pain, and long recovery—while men can more easily imagine large families in the abstract. Beneath the humor is a pointed social critique: reproductive expectations and pronatalist ideals are often shaped by those who do not pay the same biological costs. The line thus works as both a wry observation about human self-interest and an early-20th-century feminist-leaning comment on gendered labor and power within marriage.