The Inadvertent One Child Policy in Rich Countries
Larger families are de facto legally banned from most cities. The harm this is about to cause the entire industrialized world is immense. But it’s fixable.
NOTE: Elon Musk has been talking about the disaster of depopulation for several years, as I have been for two decades. The consequences of the “population explosion” turned out to be massively positive — particularly for increasing the division of labor and thus per capita wealth — while the predicted harms did not materialize (e.g., we now feed billions more people using just 1/3 of the land area for farming).
By contrast, population loss in Japan has produced what we now call “The Lost Generation”. It turns out that the Creation Mandate (Gen. 2:26-28) was the right path after all.
But you don’t have to have something as evil as China’s One Child Policy to hamstring your society. Daniel Hess here explains one way we are needlessly torpedoing ourselves. — RDM
by Daniel Hess
January 15, 2025
In a recent article, I presented a lot of evidence that high urban density lowers fertility.
Some smart people questioned the strength of the relationship and particularly the causality.1 How about this: larger families are de facto legally banned in most cities?
Urban areas dominated by high-rises have astonishingly low fertility rates
I have warned that cities that are a sea of high-rises apartment blocks have civilizationally catastrophic low fertility rates. Consider these fertility figures from last year:
Shanghai: 0.54; Beijing: 0.66; Seoul: 0.55; Bangkok: 0.8.
This isn't just an Asian thing either. Below we can see in a map the massive difference in fertility between the suburbs (mostly houses) and the urban core (apartment blocks) for Sydney (2.0/1.0), Perth (1.7/1.1), Bisbane (2.0/1.0) and Melbourne (1.7/0.9) in Australia. There is up to a 2-fold difference in fertility between the urban core and the suburbs.
In London, we see the same thing: fertility is close to 2x higher in suburban boroughs compared with the high-rise dominated City center (1.6 vs. 0.8).
This is not a minor difference. This is a difference of up to 100% in fertility, a difference between nearly sustainable birthrates and rapid demographic collapse.
What are the mechanisms? "Correlation does not equal causation."
There is in fact a very severe and direct causal mechanism at play limiting fertility in apartments. On one hand, family-sized apartments are exceedingly rare. On the other hand, rules and cultural expectations impose limits that demand larger apartments. For example, it is generally seen as inappropriate for older boys and girls to share a bedroom or to share a bedroom with parents. There is an expectation that a family with a boy and girl should have three bedrooms and in certain circumstances that is required by law.
(1) Almost all new apartments have two bedrooms or less.
As this table shows, almost all new and existing apartments in the US have fewer than three bedrooms.
There is a widespread belief among libertarian economists that low fertility in cities is simply because there is not enough housing. In this telling, reflected in economist Bryan Caplan's book Build, Baby, Build, if you remove all restrictions on building, then the market will simply give abundant housing, and the fertility crisis will be solved.
Unfortunately, these economists like Caplan have a severe misconception of what builders actually build. Large apartments of the kind that could accommodate larger families are rare outside of pre-war buildings in New York City.
Caplan's ignorance of what apartments are actually like is on display below. Bobby Fijan, a leading urban developer with a large following here on X, responds to Caplan by noting that most new apartment buildings don't have any apartments suitable for families.
This was my own experience going to rental offices in Bethesda and Rockville, MD posing as someone needing a 3-bedroom apartment. None of the buildings I visited had even a single unit that is appropriate for families. Among 1,132 units in four buildings I visited in Rockville and Bethesda one day last June, there was not a single three-bedroom apartment. I don't just mean that there were no three-bedrooms available to rent. I mean that the rental manager informed me that none existed.
(2) By modern norms, it is seen as inappropriate to for parents to share a room with older children, or for older opposite-sex kids to share a room with each other. Under modern norms a family of four would need at least three bedrooms and under certain circumstances that is actually the law.
Below is California state regulation regarding to children and bedrooms. The rule below applies to foster families and not all families, but it reflects the social norms that we live under.
To recap, if you have just two children, a boy and a girl, the modern expectation is that you should have at least three bedrooms.
Meanwhile almost all apartments being built in the United States and in most developed countries have fewer than three bedrooms.
This is a de facto one- to two-child policy for urban dwellers in the United States and many other countries.
And this limitation becomes immediately apparent when you talk to the residents.
(Why did cities have higher fertility in the past? Crowding was once the norm, but that is both socially unacceptable and sometimes legally disallowed.)
A vast gap between the theory of housing and actual practice
The strongest criticism of economists like Bryan Caplan who advocate for urban densification is not that they are hypocrites for never living in the type of housing they push for. It is that they don't even know what they are selling.
Most economists do not get how incredibly anti-natal modern apartment buildings actually are. Perhaps Caplan has a mental model of five-bedroom apartments that accommodate big families. In practice even three-bedroom units are nonexistent in most new high-rises.
Smaller units are apparently much more profitable for builders. Of course! The more paying customers you can fit into your building the more money you will make. Small units are what builders prefer overwhelmingly, given free reign. And these totally anti-natal, it turns out. Perhaps that is why fertility in a place is very inversely correlated to the share living in apartments.
We can say all day long that builders should build family-sized apartments with many bedrooms in cities. But that's less profitable. Who will force builders to build those?
When you're in a hole, keep digging?
Zvi Mowshowitz in his recent article Fertility Roundup #4 responds to my own arguments about density directly. Zvi writes, "The only way out is through. If South Korea had twice as many high rises, allowing all units to be larger at lower prices, then the fertility penalty would stop."
So here the fertility of Seoul, and Korea:
The problem with Zvi's solution? Korea has already done what he recommends, building high rise apartment towers in Seoul at a rapid pace for more than sixty years! Now more than 50% of the entire nation lives in Seoul, TFR 0.55.
And guess what: rents in Seoul are 75% lower than they are in New York! Maybe price isn't the issue after all!
I have been to Seoul on three different occasions. I found it to be harsh, a crowded place consumed by concrete, with very little greenery. But that's not just my opinion. Hell-Chosun is a word Koreans use to describe their own country. Who would look at Seoul and declare, moar? Economists, it seems. Guys, if a country disappears then there is no economy.
Admittedly, the fertility of the rest of Korea isn't great, but it is still 50% higher than in Seoul.
What kind of density is a problem?
The 2017 paper, Population density, fertility, and demographic convergence in developing countries, by de la Croix and Gobbi states, "We find a causal relationship from population density to fertility such that a rise in density from 10 to 1000 inhabitants per square kilometer corresponds to a decrease in fertility of about 0.7 children." That is a big difference in a low fertility world.
But 1000 people per square mile is not the density I am most worried about. The density of Montgomery County, MD, where I live is ~2000 people per square mile and it mostly looks like this:
Not bad for families, and workers are plugged into the economy of a major city!
By contrast Seoul has a density of 40,000 people per square mile with some districts reaching 60,000 per square mile. Catastrophic! And it isn't even necessary when most of Korea is empty.
Just keep existing rules
Am I advocating anything radical? Not at all. We already have rules favoring single family homes. We can keep most of those rules and open up more green space for building.
It is pretty sensible to say, "let's not scrap all zoning rules for the sake of Seoul-maxxing."
What about Cairo?
A critique in Aporia includes this graphic of the Nile delta and notes that Egypt has a fertility of 2.8 births per woman with particularly high density in Cairo.
But Egypt's per capita GDP is 20x lower than the United States and also a greater share believes in sharia in Egypt than in Afghanistan, according to Pew! In short, Egypt is a poor nation with a fundamentalist, patriarchal religion. Not the prescription we want, is it?
Also, unlike in the United States, there is no law in Egypt that makes crowding illegal.
Monaco and Funny Fertility Data
Monaco is frequently presented as proof that you can get high density and high fertility in a rich Western country.
Yet here is @BirthGauge on Monaco:
In Monaco, they count every child born but often not the parents! That's a recipe for wildly overstated fertility data, especially in a place where people seek to get their kids a sought-after citizenship.
Build, absolutely! But out, not up.
The Build, Baby, Build idea can be good or bad, depending on how it is applied. If it means building lots of houses like they do in Texas, you have a recipe for thriving. But if it means extreme vertical density like in Seoul, that could crash fertility and cost you your future.
— This essay originally appeared on X. Be sure to follow there as well as on Substack.
One notable critique was the article Does density lower fertility? in the online magazine Aporia. Many issues raised are addressed here.
Very interesting article Rod! My wife is from a small farming town and I lived in San Fran, DFW, Nashville and we live in Indy now. My observation is that while on the surface many larger cities are considered economic powerhouses for banking and things like tech value creation, there are also cities and towns that create and encourage family formation. Which leads us to the question, which one is actually creating value in God's eyes? God often doesn't look at value creation the way the world does.
Thanks for this. It is sadly true. I know some young parents who co-sleep with their children while they are very young, then move them into a separate bedroom later. Sometimes parents take the smaller room and put the kids in the larger. We need to get away from the idea that everyone needs separate bedrooms. Boys can go in one room and girls in another. Zoning occupancy needs to change where prices are too high. I have always admired the new ways that specialized architects and interior designers have come up with ingenious solutions to small spaces. Multifunction furniture or repurposed furniture can save space and money. Obviously, it would be better to have houses people can afford, but I don’t want this to keep people from having families.