Galaxy v02n01 (1951 04) : The Marching Morons
Anyone that’s seen Idiocracy knows this story pretty well: a man frozen in time is awoken in the far future and learned that the idiots have inherited the Earth because the smart people were too busy being smart while the dumb people were all out there breeding. The solution in this story from 1951 is vastly different than the one in Idiocracy, here they’re just straight up killing off the surplus people by making them want to take a trip to an off planet colony. The story was written before hormonal birth control was widely known of, which takes the teeth out of the threat proposed.
It’s a fun thought experiment to look back on to see what people were thinking of at the time and it’s interesting to see that the ideas we have now were expressed nearly 80 years ago in similar ways.