Japan has never had population control. China is the country that only allows one child.

However, China is now realizing that the "one child" concept is also going to cause them great grief in the next generation. Families are so focused on a son (who will take care of them in their old age) that the daughters are being abandoned and adopted by foreigners. What is going to happen is that there will be a generation of males who will not have a Chinese girl to wed and that will cause even further population issues.