Gil Hamilton wrote:Grand Admiral Thrawn wrote:Ignoring everything else, that the race would have died before they reached space?
This was the main one I thought off, since if they couldn't breed naturally, they would have died out before they had the technology to do the process or even find suitable corpses.
*gives GAThrawn a big cookie*
That objection, though, is one that does not necessarily hold. A relatively "simple" explanation would posit the following: A planet with two species, one humanoid (which one does not even have to be necessarily sapient).
One species has a normal reproductive cycle, while the other, quite possibly derived from a completely different genus, is different. This "different" species has removed virtually all biological investment in reproduction. All it needs to produce offspring is access to a freshly deceased organism that is vaguely compatible in terms of genetic coding and gross physical dimensions. A swarm of reproductive cells is injected into the deceased organism and does all the work of reproduction outside the "parent's" body. In the pretechnological state this would almost certainly require the corpse to be extremely fresh.
End result: the donor species spends time and effort bringing its young to term and then raising them until they themselves reach reproductive age, while the taker species scavenges freshly dead corpses and has a new, fully functional adult added to its ranks within a few weeks to a few months.
The near-inevitable depletion of donor species over time would provide possible impetus for technological advancement and ultimately for space travel. Of course, it would also provide impetus for the generation of death/afterlife cults and potentially for camps devoted to breeding donor material which is then euthanized and converted. Kind of a cut-rate biological version of the Borg.
All things considered, it's an almost plausible piece of Trek. Big emphasis on "almost."