Fertility Decline
causes, consequences, cures
Fertility rates are declining everywhere, below replacement in many developed countries. Even in countries well above replacement the fertility rate is falling rapidly, in Afghanistan from 7.65 (1995-2000) to 4.5 in 2022, in Angola, over the same period, from 6.75 to 5.2.
The first question is why.
Causes
Malthus, two hundred years ago, argued that because people very much like sex they would reproduce at well above replacement unless they were sufficiently poor to make rearing children a substantial burden, hence that the equilibrium was a society where the masses were not much better off than in his time. Any improvement on that would lead to exponential population growth; eventually the pressure of population against a fixed supply of land would bring incomes back down.
Modern contraception solves that problem but introduces a new one in the opposite direction. That is one possible explanation for the decline in fertility.
Another is improved job opportunities for women, more alternatives to the profession that absorbed most of the female labor force in most past societies. Women are on average weaker than men, which was one reason for the sexual division of labor in the past. Technological progress has made physical strength less important as a job qualification than it once was, so more of the world’s work consists of jobs where men have no advantage.
A third possible explanation is that, due to changed patterns of child rearing, more extensive educational requirements, and the elimination of many jobs that children did in the past, children are less able than in the past to contribute to the family income, making rearing them more of a net burden.
There is one more explanation that someone offered in an online discussion, one that had not occurred to me but probably has to many others. In past societies, one reason to accept the costs of producing and rearing children was in order to have someone to take care of you in your old age. For a couple to reliably end up with two adult children required a rate of reproduction sufficient to maintain, perhaps grow, the population.
We now have Medicaid and Social Security in the US, in other countries equivalent institutions. Having children who care for you is still valuable but less essential than in the past. Social expectations have shifted accordingly, still with some assumed obligations to parents but much weaker obligations than in the past.
Consequences
The second question about fertility decline is whether it is a good or bad thing. Sixty or seventy years ago the answer, at least among the western elite, was that fertility decline would be a good thing. Most people at the time thought in terms of slowing population growth, not reversing it, but some argued that Earth would be better off with many fewer people on it. I was a skeptic then of the population orthodoxy as I am now of the climate orthodoxy, in both cases seeing no particular reason to expect the change, population growth or global warming, to make us on net worse off, let alone much worse off.1
What about change in the opposite direction, population collapse? It too will have both good and bad effects. Future generations will inherit more housing per capita, more land per capita, an advantage for them. On the other hand, many of the things we consume are subject to increasing returns to scale, cheaper to produce per person the more persons they are produced for, so will be more costly if there are fewer of us.
An important example is intellectual property. Once a novel is written or a movie produced, the additional cost of having it consumed by one person is low, near zero now that books no longer require paper. We can expect less intellectual property to be created and, on average, of lower quality in a smaller population, all else being equal. That applies to technological progress as well, less with fewer creators to produce it and fewer consumers to pay them to do so.
There is another problem with shrinking populations, one linked to my fourth explanation for the decline in fertility, and it is the main reason people see population decline as threatening. The old still depend on the young to support them, even if no longer on their own young, and there will be fewer of them. In the past, it was in my interest to produce children to take care of me in my old age. Now it is in our interest to produce children to take care of us; the welfare state has converted children from a private good to a public good. Public goods are, for familiar reasons, underproduced.
Think of fertility decline as a problem of market failure.
The solution usually recommended for market failure is for the government to correct it but, as I have long argued, market failure exists on the political market as well as the private, indeed is more common there. The political market is, in this case, the source of the problem. It was politically profitable to set Social Security up as a Ponzi scheme, paying the early contributors more than they put in, continually pushing the increasing actuarial debt into the future, a policy that depended on an increasing population.
Even without a welfare state there could still be a problem, although a smaller one. Even on a free market, the old depend on the young; someone has to grow the food they eat. In an alternate history without Social Security and Medicare the old would pay for their consumption out of savings, investments, and private pensions, as many in large part do now. They would be living on accumulated capital, consuming goods and services produced in part by labor. A decline in the working population would produce an increase in the price of labor, a decrease in the return on capital, making the old worse off.
There are two reasons why this may turn out not to be a problem. The first is artificial intelligence, which lets machines replace men, capital replace labor, in many jobs. The second is medical progress, in particular progress in slowing aging. If age related decline sets in ten years later than it used to that is ten more years before you need to be fed by someone else’s labor.
Cures
The third question about fertility decline is what can be done to stop it.
The obvious answers, linked in order to the possible explanations, are:
Ban contraception.
Sharply restrict women’s participation in the labor force.
Subsidize child rearing.
Abolish government funding of the old — Social Security, Medicare, … .
We already do the third, could do more of it, although international comparisons suggest that it would take a lot of money to change fertility rates significantly. One problem, aside from the problem of paying for it, is that it is hard to make sure the money is spent on the children. If having a child gets the parent a lot of money that they can spend on themselves that is a reason for people who have no interest in rearing children to produce them anyway, which could have unfortunate consequences.
Subsidies to child birth are happening, here and elsewhere, but unlikely to be enough to keep fertility up. None of the other three seems likely to happen in anything close to a modern, developed, society.
There is, however a fifth option: Medical progress. Artificial wombs would reduce the cost to women of bearing children. Slowing aging would increase their time to have them. In the limiting case, if we learn to stop aging, better yet to reverse it, we will have a population more of whose members can have children and whose philoprogenitive members, even if a minority, can have a lot more children.
The sixth option is evolution. If people who are in favor of children have them and people against having children don’t, an increasing fraction of the population will be descended from the first group. If the preference is heritable, a philoprogenitive gene or culture transmitted from parents to children, birth rates should start back up. Eventually.
The US Amish population has a twenty-year doubling time.
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You should probably also mention ever-increasing standards for child rearing, particularly in countries like the US, making merely "adequate" provision for one's children increasingly expensive in both time and money.
Some additional/related explanations/thoughts:
1) Atomization of the extended family and post-industrial familial diaspora makes it more difficult to have proximate child rearing assistance that is truly loving, so having children has become more intimidating and therefore less desirable.
2) Childhood mortality has plummeted. The trend chart of childhood mortality looks almost exactly like the trend chart of fertility. In ye olden days, to be sure that enough of your children would survive that they would have enough children to survive, etc, you had to have a LOT of children. At least a few of the children you brought into the world needed to bring children of their own into the world for you to be confident that your genes would live on. For you to have three children become parents, you needed to have at least four or five be born, and even if you had that many, there was a decent chance you'd lose most of them, so you really needed to have seven or more to be reasonably confident that three might someday have children of their own. Nowadays, literally 99% of children born survive to adulthood, so if you have just one child, the pressure to have more has meaningfully evaporated.
3) School pushes back age of marriage for everyone, including women, and a woman's age at marriage is an exceptionally good predictor of how many children she'll have. I am an example: I am the youngest of four, my mother got married at 21, had her first child at 23, and her last at 33.
P.S. "Artificial wombs" 🤮
P.P.S. Your point about evolution/the Amish is a good one. The future belongs to those who show up. Antihumanists are least likely to have children. Pronatalists are most likely to have them.