Sex and the City, Pregnancy and the Suburb?

If a correlation exists between birth rates and urbanization, does the post World War II baby boom owe its existence to urban sprawl?

Photo: Sriram Khe

Earth Day was an opportunity to think about a number of issues, including about urban sprawl and population growth. And I kept coming back to the same question: would birth rates and, therefore, population growth rates in the US have been lower if we did not have the post-WWII urban sprawl?

I was a graduate student at USC many, many years ago when I first came across studies by people like Richard Easterlin -- research that examined the relationship between economic development, urbanization, and changes in demographic patterns. Well, one of the lessons there was that the economic transformation that societies underwent was accompanied by massive changes in the spaces where people lived, so much so that rural population in developed countries is now a very small percentage of the overall population. The global story is not very different either; the Executive Director of UN-Habitat, Anna Tibaijuka, recently remarked about the change in spatial distribution of population: "2007 is a year when human beings will become an urban species, homo urbanus. From now on the majority of people will no longer be rural but urban. And there is no going back for this demographic shift and transition is irreversible."

As the population moved to cities, people immediately recognized the costs of having children. As opposed to the rural life where children might have contributed to a family's earnings by working on the farm, for instance, urban children required parents to invest both money and time in them. And as adults became more and more engaged in modern economic activities in urban areas, they found it increasingly difficult to invest the time and money in children. Further, in the cities there was a premium to pay for larger dwelling sizes too. To top it all, as women entered the workforce, the opportunity cost of having children dramatically increased, which then contributed to further decreases in fertility rates.

So, in this context, what if the post-war suburban growth had not happened the way it did? What if the returning GIs had married, yes, but had continued to live in densely populated cities? Of course, it is not easy to estimate counterfactual historical scenarios that Niall Ferguson seems to enjoy in his profession. Yet, it is difficult to resist speculating whether the absence of suburban growth and urban sprawl might have changed the recent demographic history of the US.

Studies that criticize urban sprawl often point at Western European countries or Japan as examples of compact cities and smart growth. In these countries, families and households live in units that are significantly smaller than the average American dwelling unit. About two years ago, I asked a visiting Japanese faculty from Saitama what according to her was the biggest difference between Japan and the US. Without hesitation she replied that it was the amount of space here in the US. Later in her guest lecture in my class, my students could not believe that she and her son lived in an 800-square feet apartment.

Japan and Western European countries are also places where fertility rates have steadily decreased since the end of WWII, to levels that are significantly below replacement-levels. Interestingly enough, some of the other areas with very low fertility rates -- such as Taiwan, Singapore, and Hong Kong -- are also characterized by metropolitan areas with high population densities.

On the other hand, birthrates in the US did not precipitously fall after WWII as they did in Western Europe and Japan. The typical story of the post-war years is one of GIs returning home, getting married, moving to the Levitttowns across the US, and raising children. Immigration to the US and their fertility rates do affect the story, no doubt, as does the withdrawal of women from the workforce and back to the traditional roles of homemakers.

Counterfactually though, if there were no Levittown and no suburban expansions, and if the young families had stayed back in the cities, then would the cost of urban life have dampened the propensity to procreate, particularly with the simultaneous technological advancements in family planning and birth control? Was urban sprawl then a reason why the US did not go the European route when it comes to birth rates? After all, even now it appears that the more compact New England areas have lower birthrates compared to the sprawling cities in the South and the West.

If such a counterfactual scenario is true, then it could imply that the higher fertility rate in the US, compared to other developed countries, is the unintended consequence of government subsidies in the form of freeway and road building, low gas tax and, hence, relatively inexpensive gas, deductibility of home mortgage interests from income taxes, etc. These helped disperse the population from dense population settlements and led to low density suburban settlements -- urban sprawl -- where fertility rates are higher than rates in Western Europe.

Every once in a while, in the introductory geography class that I teach, I ask students to collect fertility rate data on their respective families going back to at least their grandparents and preferably back to their great-grandparents. A typical trend that we then observe later in the class discussions is that fertility rates have, as a class average, decreased over the generations. The other trend we observe from their data is a correlation between fertility rates and whether or not their mothers and grandmothers lived in cities or the rural areas -- almost always students from large families came from rural areas. Even these "micro" case studies highlight the possibility that if Americans had stayed in cities in large numbers, instead of moving to the suburbs, then the birthrates may have been much lower. So, yet another reason to praise, or vilify, urban sprawl?

Sriram Khé is an Associate Professor of Geography at Western Oregon University. Prior to this, he taught at California State University-Bakersfield, and was an Associate Planner with the Kern Council of Governments.



Michael Lewyn's picture

inconsistent with the facts

The attempt to correlate sprawl and the baby boom is based on the assumption that sprawl in large part occurred all at once- that as soon as World War II ended, cities collapsed and highways were built within a couple of years. But this assumption is factually wrong.

The reality is that a few cities began to lose population in the 1950s, but the most devastating population losses were in the 1960s and 1970s. If the sprawl/baby boom correlation was true, we would find a baby boom beginning in the early 1960s. In fact, the baby boom ENDED at about that time.

Interesting theory

Actually, if you think about how people move and have children, it would make sense that the biggest movement to the suburbs came a bit later; it's not the first two kids that make it hard to live in a dense city but the third or fourth...

Michael Lewyn's picture

nice try...

but flawed in a variety of ways:

1. If people were having their first babies in 1945-50, the third and fourth children were probably in the early and middle 50s- still long before the 1960s-70s tidal wave of suburban migration.

2. If increased house size and high birth rates went together, we would expect to find birth rates rising as house size increased. But in fact, birth rates have been nosediving in America for some decades;

3. If its so hard to live in dense areas with several children, how come the Hasidic Jews do it so easily? Kiryat Joel, a Hasidic NYC suburb, has 11,000 people per square mile, and the average household has six people,_New_York#Demographics


It has been more than two generations since the last vestiges of the home mortgage interest deduction had any form of sprawl inducement. Will the HMID ever get a fair hearing?

Do you need a big suburban house to have a big family?

Travelling around the world, in areas that are both urban and rural, I've always been struck at how happy families are living in about 200-300 square feet for 6-8 people. Most rural areas I've visited have had much smaller homes and more people per square foot living in them than more densely populated areas where people still have 3-6 children.

Therefore, if we apply this lesson to the United States, the baby boom didn't likely cause sprawl and the ability to sprawl didn't bring on the baby boom. That is, the two are completely separate phenomena.

Indeed today, houses are bigger than ever in the USA, and yet families are smaller.

I suspect that the theory about costs (or perceived costs) of raising children in the USA is accurate. By perceived costs I mean the idea that every family needs a large home, 2 cars, children in high fashions, children signed up for every expensive activity, a private school education, etc. etc. The fewer children, the more we can spend on them, and the more we see our neighbors spend, the more we want to spend, etc.


I wrote about this in

I wrote about this in Planetizen a few months ago. It was titled "Our Own Private Idahos", and is at So, I shall try not to repeat those ideas here, and will instead focus on clarifying a few other points.

Perhaps my essay does not clarify that I am not writing strictly about the boomer generation. That demographic slice is only a part of the story. My point was that we don't know how much, if any, the dispersal of households to the suburbs helped maintain a higher fertility level in the US. Even now, with the millennial generation, we notice that the fertility levels of their parents are significantly higher than the counterparts in other developed economies, and even many developing economies, where households live in more compact spaces.

Another way to look at this issue is this: governments in countries like Russia and Sweden are trying to provide monetary incentives to women in order to encourage them to have children. Could it be then that the US policy that helped the dispersal has had an unintended consequence of promoting procreation? it is almost as if we told women and families, "look, we will give you lots of space to raise kids, subsidize your transportation, etc. Will you please have children?" :-)


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