What is the impact of strict population control?

Posted by Dave on March 25, 2010 | 4 Comments

We’ve discussed some of the problems with increasing population, particularly in poorer countries. But what do attempts to deal with those problems look like?

China has implemented a notorious “one-child” policy since 1979 — over thirty years. While most people agree that this policy is a serious violation of human rights, the example of China is still a useful case study for understanding the effect of dramatic population control. In 1970, China’s fertility rate — the number of births per woman — was 5.9. Obviously in a country already struggling to feed its population, this was cause for alarm, potentially doubling the country’s population in less than 30 years. But by 1979, when the “one-child” policy was implemented, the fertility rate had already declined to 2.9. It might be reasonable to conclude that the Chinese fertility rate could have continued to decline without any government interaction, but of course, this isn’t certain. Fertility in the nearby regions in Asia have indeed declined: Singapore is 1.04, and Japan is 1.38. But Afghanistan and Pakistan’s fertility rates remain stubbornly high. Take a look at this graph (from Google Public Data — slightly different data from what I cite above) comparing these countries:

In the wake of the “one-child” policy, the Chinese fertility rate was reduced to 1.7 by 2004. While that’s an impressive decline, it makes it quite clear that “one-child” is a bit of a misnomer. Only urban women and government employees are limited to one child. In other areas, families are allowed to have a second child after five years if the first child is a girl, and in remote areas, families can have three children.

But as you might expect, sharply reducing the fertility rate can cause other problems. While not as high as in some other countries, the proportion of elderly Chinese has increased dramatically. Therese Hesketh, Li Lu, and Zhu Wei Xing have conducted two reviews of the one-child policy. They say the proportion of Chinese over 65 increased from 5 percent in 1982 to 7.5 percent in 2004. It’s expected to grow to 15 percent in 2025 — a large number of retirees, but still below Japan’s current level of 20 percent. In China, however, offspring are expected to care for their parents in old age. If each family only has one child, then this could mean two people are caring for up to four elderly parents. This has led to a revision in the one-child policy: Couples who are both only children can have two children. China is also considering modifying its pension policy to provide more government support for the elderly.

But perhaps the most dramatic impact of China’s one child policy may be on gender distribution. Male children have traditionally been favored in Chinese culture, so families in the past just kept having kids until male children were born. If you’re only allowed to have one child, then that strategy doesn’t work. While rumors are rife of infanticide of female infants under one-child policy, the much more common strategy appears to be sex-selective abortion. Though this is technically illegal in China, private companies offering gender testing have sprung up, and abortion is readily available, so the law is difficult to enforce.

Because of the legal issues involved, it has been hard to estimate the sex ratio of births in China, but Hesketh’s team came up with an innovative way around that. They analyzed 2005 census data in China, simply counting up the number of males and females at ages 0-1, 1-4, 5-9, and 10-14.

This graph shows the results:

As you can see, there’s a dramatic difference in the number of males compared to females, with an average of 124 boys for every 100 girls age 1-4. This can lead to troubling social problems that go beyond men simply not being able to marry. The lack of women can lead to an increase in prostitution and other sex work. Unattached men may be more likely to commit crimes and participate in social unrest. Interestingly, the researchers observed a pattern of sex ratios that relates to differing one-child policies in different regions:

Notice that the highest sex ratios occur in regions with a “medium” policy, where women are allowed to have a second child when the first child is a girl. This might mean that simply changing the policy could have an important impact on the sex ratio. One possibility would be to allow all families to have two children, regardless of sex. This could lead to families with boys having additional children, increasing the chances of girls being born.

But perhaps the most important lesson about China’s policy is that government-imposed population control measures can have significant unexpected consequences. While few are suggesting such dire measures be taken in other countries with precarious population growth, even simply promoting more birth control or allowing more abortions in those countries might end up causing population imbalances that could have adverse effects for decades.

Hesketh T, Lu L, & Xing ZW (2005). The effect of China’s one-child family policy after 25 years. The New England journal of medicine, 353 (11), 1171-6 PMID: 16162890

Zhu, W., Lu, L., & Hesketh, T. (2009). China’s excess males, sex selective abortion, and one child policy: analysis of data from 2005 national intercensus survey BMJ, 338 (apr09 2) DOI: 10.1136/bmj.b1211

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