Vasectomies
This is building up on the ban that the Chinese government had in place for multiple children in one family. The population was declining so fast that hospitals panicked and reported the problem to the officials. They in turn thought that a quick solution would be to ban vasectomies in the country.
While we do not really know if that was the sole reason for the population to decrease rapidly, we think it’s a law made in haste. In recent years, vasectomies are back on the table as an option for men, but they need special permission to have them done, not just anyone can go get one.