Explaining fertility transitions.

In this essay, I suggest that the crisis in our understanding of fertility transitions is more apparent than real. Although most existing theories of fertility transition have been partially or wholly discredited, this reflects a tendency to assume that all fertility transitions share one or two causes, to ignore mortality decline as a precondition for fertility decline, to assume that pretransitional fertility is wholly governed by social constraints rather than by individual decision-making, and to test ideas on a decadal time scale. I end the essay by suggesting a perceptual, interactive approach to explaining fertility transitions that is closely allied to existing theories but focuses on conditions that lead couples to switch from postnatal to prenatal controls on family size.