Chinese One-Child Policy poster (The Galloping Beaver)

Whoa. Here’s something I didn’t expect to happen within my lifetime: Last week, China officially ended its one-child-per-family policy. Now, married couples are allowed to have up to two children. Crazy! (Though I kind of doubt that many couples will get crazy, and have more than two.)

The one-child policy was informally adopted (i.e. “strongly encouraged”) in 1975, made into law by the country’s Communist Party four years later. The law followed China’s population exceeding 800M+ people in 1970, with leaders realizing that the then-current growth rate was unsustainable.

However, the law has been relaxed for exceptions. In 1984, parents were allowed to have two children if one parent was an only. In 2013, this became alright if only one parent was an only child.

It’s estimated that the policy has prevented 400M+ births.

But why was the policy abolished, and why now? There are a few reasons. One is that the male-to-female sex ratio is becoming unbearably skewed, which tends to happen when preference for one sex greatly outweighs the other. (In this case, the Chinese preferred boys to girls, even going so far as to commit infanticide if a child was born a girl.) The birth rate is also declining, and the mortality rate is on track to outpace it. Per “The New York Times:”

China’s working-age population, those 15 to 64, grew by at least 100 million people from 1990 until a couple of years ago. But that expansion is petering out, and more people are living longer, leaving a greater burden on a shrinking work force. Now, about 10 percent of the population is 65 or older, and according to earlier estimates, that proportion is likely to reach 15 percent by 2027 and 20 percent by 2035.

China’s population is now 1.3B+, with 30% being over 50. It’s estimated that the decision will affect 100M+ couples.