After 35 years, China’s One Child Policy has come to an end. Carried out with high compliance and across a large population (at scale a decision is at greater risk of second-order effects) the policy had unexpected outcomes.

The One Child Policy has been a common topic over the years (even the Economist published a recent article on “The Law of Unintended Consequences,” about changed attitudes in China toward family size). Let’s look at what happened over the last 35 years and why.

Consequences of the One Child Policy. Which are expected outcomes?

Ultrasound machines were known, though rare in China, when the One Child Policy was enacted. When it was typical to have large families, while the preference for boys absolutely existed, it was a lower stakes “game,” played over multiple pregnancies. When the game changed into one that was only played a median of one time (one child), the stakes changed dramatically. And then, when ultrasound technology made it possible to know the gender of a fetus in utero, gender-based decisions on whether to bring the pregnancy to term became possible. For attitudes that take time to change, and given the length of human maturity and gestational periods, there is also time to realize the change.

Given this, I believe that most of the outcomes below were predictable in direction (what will increase) though not in magnitude (how much an outcome will increase).

• Larger gender imbalance. If you start with a population that has even a small preference for one gender over the other and introduce a limit of only one child (the either/or choice), then the gender imbalance will grow. It’s a question of how fast.

Today, at-birth sex ratio in China is estimated at between 1.15 to 1.19 male to one female.  The expected ratio is 1.06 boys to girls born, while the world average ratio is 1.09 (higher than expected because of intervention). The human gender balance at birth is slightly higher for males in part due to more female fetuses being lost naturally during pregnancy.

• Faster adoption of new ultrasound technology. When the stakes changed, news about this new technology spread quickly and machines were imported and produced domestically. In business, we’d call this reaching product-market fit, though it is the rare case of the market and not the product changing.

Chinese availability of the first domestic ultrasound machines coincided with the start of the One Child Policy. This timing had massive impact. The speed of dispersal is not surprising for technology that serves such a high-demand need. Ultrasound machines went from nearly zero in 1980 to being present in 80% of counties by 1988.

Gender in utero is visually apparent due to human physiology. If people wanted to select for another physical trait, such as handedness, ultrasounds would not have had an impact and distribution would have been slower.

• Creation of a black market for ultrasound gender identification. After the prohibition in 1994 of using ultrasounds to determine fetus gender, the technology was already widely available enough to circumvent the prohibition. As long as the technology exists and the impact is large, people will seek out practitioners who circumvent the ban.

• Lower suicide rates for women. China was one of the few countries where suicide among women is higher than men. The claim from a paper that ultrasound adoption led to a decline in female suicide is problematic (exchanging higher adult survival for gender-based abortion), but it is an interesting point.

• More men who cannot find women to date or marry. Taking the economic view on this. Competition among heterosexual men increases as there are fewer potential dates or mates. Expectations rise in type of home, car, and lifestyle as signs of worthiness. Women in general gain more selectivity in choice of dates or husbands, which pushes up minimum requirements. However, this change has also left some women with top degrees and jobs priced out of the market.

• Extra attention paid to the only children. The 4-2-1 family structure (four grandparents, two parents, one child) means that there are six people focused on the only child. The term “little emperors” comes to describe spoiled children, a new problem at scale. This attention has also meant that more family income is spent on education, food, and experiences than otherwise. Going back to larger families would mean that this level of attention to each child would decrease.

• Less ability to depend on family for support in old age. When children outnumbered parents and grandparents, the family provided the safety net for the older generation. This will be less possible as 4-2-1 families age, requiring governmental support. This may be a larger problem in China, where it is common for payments within families to flow first from parents to child and then, as the children become adults, back to the parents.

Looking Ahead

The One Child Policy in China partially helped the problem of overpopulation, but also created other problems by exaggerated the problem of gender imbalance. This alone does not mean that the One Child Policy should not have been created in the first place.

Given the relatively long gestational period of humans and how data on practically every birth is collected, problems created by the One Child Policy can also in theory be reversed by a change in policy. The tricky part is whether preference for one child (shift in attitudes, shift in economics of child raising) continues even after the policy’s end. Other countries with low birth rates (which were low without government intervention) have had difficulty increasing birth rates through government subsidies for larger families.

A reason given for wanting to end the One Child Policy is the connection between population growth and economic growth. This reason seems problematic. Set aside the fast economic growth in China (annually upper single digits) in the last 30+ years (say, 1980s to today) and slow or negative in the early 1900s to 1970s (the impact of feudalism, civil war, and then going from capitalism to centrally planned communism). As China become capitalist again starting in the 1980s, the country has created more wealth at a rate beyond any connection to population growth. Population itself was not the problem. The problem was rather moving a large agricultural and low-skilled society to an urban and high-skilled society. There are still hundreds of millions in the country who could move along that path. Or, if you have read the Rise and Fall of American Growth,  you might say that growth in China followed a different trajectory, given how the country was held back in the last 150 years. Is slower population growth a true problem?