I'm looking for a short story (similar to Harlan Ellison, maybe even by him). When people die, their souls go into this universal god/spirit/whatever, and when a new person (or alien) is born, a bit of this spirit cloud goes into the baby. People have to learn lessons/experience what happened in their past lives.
Probably 1990s or earlier.
Could have been in Omni, or some collection of short stories.