[LS]

These things turn on a dime. There were dire warnings in the 1920s about declining population, right before France, Germany and Russia began to pump out new waves of kids.

[Dr. Sivana]

These things turn on a dime.

No, they do not. If you are at the edge of a demographic cliff, even if you start having more children, it will be 20 years before they can be contributing adults, and except for the occasional set of twins, you are only going to see one child every couple of years. The population drop-off in the '20s was nowhere NEAR as severe as what we have now.