The Academic Origins of China's One Child Policy

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In our latest Freakonomics Radio podcast, “Misadventures in Baby-Making,” we describe an academic paper by a Dutch mathematics professor that might have been one of the inspirations of the controversial One Child Policy in China. 

Here’s the story: in the early 1970s, Geert Jan Olsder co-authored the paper “Population Planning; a Distributed Time Optimal Control Problem.” He saw population as a mathematical constraint problem, where an optimal birth rate could be found:

“Given a certain initial age profile the population must be “steered” as quickly as possible to another, prescribed, final age profile by means of a suitable chosen birth rate.”

The model considered the natural birth rate and mortality rate, an economic constraint, and time. And like any good empirical scientist, Olsder makes this warning in his paper:

“This paper is not concerned with the social and political problems involved in establishing the best mechanism for a program of population management….The optimal birth rate may unbalance the age distribution during the time interval concerned, which could give rise to economic and social problems.”

He meets Song Jian, a visitor from China with a Ph.D. in engineering from Moscow University. According to Olsder, they went out for beers and talked about population planning. Olsder thought nothing of it.

Song was a ballistics missiles specialist, but by the end of the 1980s he had established a theory of population control in Chinese political and science circles. Susan Greenhalgh, an expert on the One Child Policy who served 10 years at the Population Council, notes in her book that Song formed his theory largely based on ideas from the Club of Rome publication The Limits of Growth — a 1972 Malthusian work that hinted at catastrophe if resources and population were not balanced. It applied straight forward equations to economic outlooks without data, an approach that economists have since dismissed.

Armed with The Limits of Growth, along with computations and models that called for drastic policy change, Song took his hard science approach to powerful party leaders in Beijing. Here’s Song’s bio from the China Daily website:

“With his knowledge of cybernetics, Song worked out a theory of a bidirectional limit to the total fertility rate. This helped the Chinese leader to formulate the state family planning policy, particularly the “one couple, one child” policy.”

The rest is history. Three decades later, the policy has led to severe gender imbalances in some parts of China, which is also facing a potential demographic disaster due to its aging population. Ironically, China might have the opposite population problem now: too low a birth rate.

For more on Song Jian and the One Child Policy, check out Mara Hvistendahl‘s piece in Science.


Well..... #1 to say that "the policy" has led to severe gender imbalances is not accurate. Having a restriction on the number of children couples are allowed to have doesn't, by itself, cause a gender imbalance. What causes the gender imbalance, presumably, is parents choosing to have selective abortions, which is, by the way, against the law in China.

In addition to that, there is nothing to say that even without the "One" Child policy, (which actually allows many people to have more than one child), that this type of gender selective abortion wouldn't still be taking place, indeed it is known to take place in other countries that have no restrictions on childbearing. The gender imbalance is similar actually in India, its not quite as high, but its close.

Furthermore, there have been no studies to confirm that 100% of the gender imbalance is due to selective abortion, who knows what kind of biological and environmental factors may be at play? Given that these types of imbalances are present in other dense populations, we can't at all rule out the possibility that there are other factors at play here, and if the likelihood of having a girl goes down in response to high population density (studies have shown a link to environmental stress and the rate of having boys) then the ratio could be similar to even more skewed without the policy.

#2 Focusing only on demographic issues fails to acknowledge the positive benefits of the One Child Policy, and the ways in which it has benefited the country. It's not as if they are implementing this for fun, it's because they are in a dire situation. Yes, there certainly are cons to the policy, but there are also pros, and the question isn't whether there any cons or not, its whether the pros outweigh the cons.

Several papers have concluded that the One Child Policy has done more than any policy or technological development in the world to reduce environmental harm. In other words, the estimate of the resources that would have been used by the number of people estimated not to have been born in China due to the policy, trumps the positive environmental impact of all other policies and technologies.

And as for the demographics issue, supporting the elderly isn't just about demographics, its about a combination of demographics and productivity, and it is certainly possible that it can be easier to support an elderly population of 25% than of 10% if the working population in the society with a 25% elderly population is more productive. In other words, if the One Child Policy increased economic growth, or GDP per-capita, then it can still actually make supporting retirees easier, i.e. it may be easier for 60% of the population to support 25% of the population if their incomes are higher than for 75% of the population to support 10% of the population with lower incomes.

Furthermore, the "demographic disaster" listed in the linked article on Forbes projects that 24% of the population will be seniors by 2050, while the Census Bureau projects that by 2050 20.7% of the American population will be 65 or over, so the difference between the two countries is only about 3%. I fail to see how a set of policies that yields a 3% difference in the portion of the elderly population constitutes a "demographic disaster".

This article and the Forbes article come off as other more than biased special pleading and a distortion of the facts.



As far as supporting an "elderly" population, there's nothing magic about age 65. I certainly don't expect that when I reach that age, my brain and body will suddenly atrophy, so that I'll be unable to do any sort of productive work. Nor do I think I'm unique, or even unusual: there are plenty of "elderly" people out there doing productive work, and there would be many more if social conditioning and mandatory retirement hadn't brainwashed so many into believing that retirement is a desirable goal.

Robert Magill

Sorry, China's one child was the direct result of Chairman Mao's "Hero Mothers" effort. Women who had four or more children got laudits and perks. In 30 years China's population rose from
five hundred forty thousnd to nine hundred thousand.
Mao died.
The new regime had to do something fast.
more at