Elves, or Gods-and-Mortals?
It seems that injecting GDF11 protein from young mice into older mice wakes up their stem cells, repairs DNA and otherwise seems to reset the aging clock. The scientists are very excited.
So, fountain of youth? Agelessness? (I prefer that term to ‘immortality’, which doesn’t apply.) Maybe yes, maybe no. Certainly not now, if at all, and I doubt in time for you or I. Nonetheless we now have to start planning ahead. Science-fiction stories need to be written! Assume rejuvenation; what then? It’s a change in basic biology! It’s bound to have huge knock-on effects. Biggest impact; the need to restrict breeding. Demographics will not be denied.
Given cheap anti-aging treatments, I see two possible stable states. One is a society with a large middle class that can afford agelessness, but not child-raising; so most live long lives but breeding is the privilege of the rich. Another is a society where anyone can breed, but 99% are too poor for the treatments; so long life is the status symbol.
There’s a third option; population explosion. But that’s not a stable state.
I nickname the first stable state ‘the Elves’, and the second stable state ‘Gods and Mortals’. Elf-world has downsides; everyone will grow up a rare spoiled trophy brat, doomed to disillusionment by adulthood. In the long run genetic diversity will fall, unless they compensate via biotechnology. Upside is that a large ageless middle class can support advanced technology. Gods-and-mortals world will be genetically robust, but divided, oppressive and backwards. I vote Elves.
So here’s your SF story; two such worlds meet and compete. Who wins, Elves or Gods-and-Mortals?