Reuters/Stringer
The law is not the most popular, and there have been some unintended consequences, including a skewing of the population towards males and a disproportionate representation of elderly people.
Still, many argue that it has been important for the country, as it has helped reduce famine and limited a population that was rapidly growing.
With the policy in place for over 35 years, the current population still rests at around 1.4 billion.
These photos from Reuters are good examples of how crowded the country has become.
(Captions by Reuters and Jack Sommer)