In the 1970s, Paul Ehrlich tried to warn us: human beings were in trouble. We were reproducing so rapidly, Ehrlich opined, that millions of us would soon be starving.

Ehrlich got one thing right: we are in trouble. But he pletely wrong about overpopulation. Today, just the opposite is true. There aren’t enough of us human beings. And a lot of people are seriously disinterested in making more.

Nicholas Eberstadt calls this the “flight from family.”

All around the world today, pre-existing family patterns are being upended by a revolutionary new force: the seemingly unstoppable quest for convenience by adults demanding ever-greater autonomy. We can think of this as another triumph of consumer sovereignty, which has at last brought rational choice and elective affinities into a bastion heretofore governed by traditions and duties—many of them onerous. Thanks to this revolution, it is perhaps easier than ever before to free oneself from the burdens that would otherwise be imposed by spouses, children, relatives or significant others with whom one shares a hearth.

Yet in infancy and childhood and then again much later, in feebleness or senescence, people need more from others. Whatever else we may be, we are all manifestly inconvenient at the start and end of life. Thus the recasting of the family puts it on a collision course with the inescapable inconvenience of the human condition itself—portending es and risks we have scarcely begun to consider.

It’s ing a rarity for American children to live with their married, biological parents. Europe’s most rapidly-growing “family” is the one person household: an adult, with no children and no relatives. Japanese women are choosing more and more not to marry. Even in the Arab world, where family has been sacrosanct, women are choosing not to marry or to delay marriage. All of this reduction of family, Eberstadt says, is adding up to a significant problem:

[T]hese voluntary changes also have unintended consequences. The deleterious impact on the hardly inconsequential numbers of children disadvantaged by the flight from the family is already plain enough. So too the damaging role of divorce and out-of-wedlock childbearing in exacerbating e disparities and wealth gaps—for society as a whole, but especially for children. Yes, children are resilient and all that. But the flight from family most es at the expense of the vulnerable young.

That same flight also has unforgiving implications for the vulnerable old. With America’s baby boomers reaching retirement, and a world-wide “gray wave” around the corner, we are about to learn the meaning of those implications firsthand.

The “flight from family” means flight from economic stability, the benefits of an extended family “safety net,” and the ability of many nations to care for their aging populations. The question is, is it too late to reverse this?

Read “The Global Flight From the Family” at The Wall Street Journal.