I’ve been revisiting a number of texts on declining fertility, and one fact remains striking above all: birth rates are falling everywhere. Across civilizations, across economic systems, among the religious and the secular alike. From time to time, a government program manages to slow the decline or stabilize fertility—but only briefly.
A few regions still stand apart, places that remain, in some respects, socially closer to a premodern world—Nigeria and parts of its neighborhood, for instance. Yet even there, this is likely only a matter of time. It is also a matter of economic conditions. In extreme poverty, when people are malnourished and struggling to survive, fertility is not especially high: weakened bodies are less fertile, miscarriages are more common, and infant mortality must be taken into account. As societies grow wealthier, people gain the ability to choose. The highest population growth tends to occur somewhere in between. After all, Europeans themselves multiplied and spread across continents in the generations following the Industrial Revolution.
So why is fertility declining?
The answer may be uncomfortably simple. Having children is beneficial—for governments, for society at large, even for extended families. Grandparents enjoy grandchildren; children benefit from growing up with siblings and cousins. In almost every abstract sense, larger families are a social good.
But there is one group for whom this arrangement is not advantageous at all—the parents. They bear the overwhelming share of the costs.
And so the familiar appeal appears: be moral, make sacrifices for society, ask nothing in return. Unsurprisingly, it does not work.
Even for those who genuinely see children as an enrichment of emotional life, one child is often enough—as the American economist Tyler Cowen has observed. Three children do not necessarily produce a richer emotional life than one. Quite the opposite: more children often mean more fatigue and stress, leaving parents with less capacity to enjoy even the one child they have.
Of course, individual experiences vary. But the underlying trend is clear enough.
What we are facing is not a marginal problem. It suggests that the old social model—where private costs and public benefits could be quietly misaligned—is no longer sustainable. A fundamentally new model will be needed.