"Living Space" is a science fiction short story by American writer Isaac Asimov.
If the chance of life arising on any one of them is about 50%, then half the time a random choice of a parallel universe will lead to a dead Earth.
As there are still an infinite number of dead Earths, they can never be filled up, and nobody is worried about the population becoming two trillion in fifty years or so.
At the Housing Bureau are two co-workers; Bill Ching, who believes fervently in the parallel Earths as the solution, and Alec Mishnoff, who worries about something he only hints at to others.
After a confusing conversation, Mishnoff realizes that the man is from a parallel Earth where Nazi Germany conquered the entire planet.
Just then Ching rushes in with another customer complaint - someone is worried about the red creatures with tentacles who are peering into his glasshouse.
He led the German tribe in one of the wars of the twentieth century, just about the time the Atomic Age started and true history began.")