One could imagine a societal model where the number of children is restricted instead of access to life prolonging technology. So to target a stable population,

One could imagine a societal model where the number of children is restricted instead of access to life prolonging technology. So to target a stable population, you'd allow people to have only as many children as people have died in the last couple of years. It's doable, we already had societies that deployed such restrictions on a scale similar to the global human population. Whether it should be done is another question, as many people criticize the issue of the state policing procreation.