Many nations have set out to control their populations. Some have adopted pronatalist policies that offer incentives for having large families. More commonly, nations have adopted antinatalist policies to decrease their population. Most population control advocates aim for zero population growth (ZPG), under which the average couple has two children (replacement fertility). This results in no net population growth.

More restrictive population policies call for negative population growth (NPG). In China, for example, each couple is permitted to have only one child. Although it is considered coercive by many, the policy has not met with any organized opposition by the Chinese people. It may be that the Chinese have accepted the one-child policy, while many in the West find it objectionable, because of cultural differences.

Population is affected by much more than just whether the government provides...