That reminds me of James Morrow's This Is The Way The World Ends.

After a nuclear apocalypse wipes out most of humanity, the ghosts of now-will-never-be-born future people hold the survivors to trial because they're ticked off at losing their opportunity to live.

There is only one ethical way to solve that moral issue: Schrödinger birthing

That doesn’t work, on multiple levels. Existing is a prerequisite to wanting; you cannot want if you do not exist. But even if you ignore that, it’s not immediately ethical or unethical to do or not do something just because someone else wants it. But even if you ignore that too, there’s no way of knowing that child won’t be the next genocidal despot. And even if you ignore all that, you could never birth even a fraction of everyone who could ever be born, since those depend on genetics and you can never have every combination of human mating with the other half.