Det är "En ögonblicklig smak" ( se även ) av "James Tiptree Jr" (en pseudonym för Alice Sheldon, vars död var som du beskriver).
Overcrowded Earth sends out an expedition searching for a habitable planet. They discover one but are uncertain if they should send back a green or a red signal which determines if a fleet of colonists would be sent out. But the aliens they found are in fact the "eggs" which the human "sperm" must fertilize, a momentary taste that forms "some kind of holy … zygote" which has a "ghostly life among the stars". What happens to humanity after that remains unsure but the last remaining crew member, psychiatrist Dr. Aaron Kaye, speculates that it will be drained of all purpose: "We’re left … empty … What happens to a sperm’s tail … afterwards?"