Voluntary birth control methods only work on the people who choose to use ’em. A population check that doesn’t work on everybody doesn’t work at all,… - Damon Knight

" "

Voluntary birth control methods only work on the people who choose to use ’em. A population check that doesn’t work on everybody doesn’t work at all, because it simply breeds out the ones who use it. The only population check that really works is one that affects everybody, like a limit of space or food.