[somenameforme]

In the 80s Iran had a fertility rate of 6+ and was one of the fastest growing countries in the world. So fast in fact that it scared their political leadership, so they 'pulled a China', a much less well known one. [1] They started putting out massive propaganda against large families, introduced widespread birth control measures (and mandates), and so on.

And, like China, it worked too well. Their birth rate fertility rate dropped from above 6 to below 3 in less than a decade. But then it kept falling, to the point of unsustainability. They realized they'd made a huge mistake so they began efforts to try to reverse it. Yet, like China, that has generally been a complete failure.

This is one of the most insidious things about fertility rates. They're not terribly difficult to send low, even to extinction trajectory low. But getting them back up is something that nobody has yet managed to achieve.

[1] - https://en.wikipedia.org/wiki/Family_planning_in_Iran