A single tiny cell had decided the fate of a population pressed so close to the ultimate limit of the planet’s resources that there was no margin for… - Lester del Rey

"But it won't stay at this level. Not with the Eleventh Commandment. They won't stop, even when there are a hundred billion."
Epstein shook his head. "They won't get there. At the present time, conditions make the death rate about equal to the birthrate. Sooner or later, everything reaches its own level. Oh, if the Australian scheme goes through, we may reach a twenty billion total. Beyond that, the more children get born, the worse conditions get—which brings up the death rate and cuts the figure back again."
"And leaves the misery rate at a maximum."

He was sure there must be some catch. Every principle here had an opposite, and both were wrong.

“You really are a pig,” she decided coldly.
“You’ve got your snout in the trough here too,” he reminded her.