The adoption of agriculture during the Neolithic triggered the first demographic explosion in history. When fertility returned to its original level, early farmers found themselves more poorly nourished than hunter-gatherers and working longer hours to make ends meet. We develop a dynamic, price-theoretic model that rationalizes these events: in the short-run, fertility and utility increase; in the long-run, consumption, leisure, and utility fall below their initial levels. This, we argue, can be attributed to the rise in child labor productivity that followed the adoption of agriculture. Counter-intuitively, an increase in the productivity of children may lead to a permanent reduction in utility.