My Soul Cried the Spaceman by Levin A. Diatschenko

The spacecraft Wanderjahre finds a coffin floating in space. Bringing it inside the ship, Captain Spendthrift discovers a Gleamer (sentient robot) inside it. The captain follows the coffin’s trajectory back to a nearby planet and finds its major cities engaged in continuous funeral processions with hundreds of coffin-bearers. The coffins are identical to the one Spendthrift had picked up. There are many planet Earths, all linked across dimensions by the force called gravity. All known Earths share similar historical and political backgrounds (though with varying emphases) but Earth 13 stands out bizarrely. The men there die on consummation, and the women only weeks after childbirth. The children inherit the combined memories of both parents, while the population shrinks. Millions of people from other Earths flock to the funeral planet, and wait with bated breaths for what may be the last Thirteener – one person with the knowledge of an entire species.