It’s easy to lose sight of the possibility (likelihood) of civilizational decline in tyrannies — as if only Western style democracies can stumble into demographic traps. Perhaps we suspect that there’s something cultural that permitted the tyranny and will negate Western rules of thumb.
But as Joseph Bottum points out, in Iran, the population has taken a downward turn, and many productive youths are looking to escape:

Birthrates tell us something about the feeling a people has for its own future, and the collapse of Iran’s fertility is the fastest ever observed. Fifteen years ago Iran had 6.6 children per female. The number today is well below 2. “A first analysis of the Iran 2006 census results shows a sensationally low fertility level of 1.9 for the whole country and only 1.5 for the Tehran area (which has about 8 million people),” Tehran University demographer Mohammad Jalal Abbasi-Shavazi recently observed. …
Of Iranians fifteen to twenty-nine years old, 36 percent said that they wanted to emigrate.

Those trends will only increase in the wake of this summer’s crackdown.