My last question was closed of being "too broad" so I've decided to add some more details to my world and then ask a more specific question. In our world The latest generation of humans mutated a gene that keeps them from aging. They still mature of course but they never start ageing (For those of you that don't know most humans reach full maturity around age 25 so imagine a world with lots of 25 year olds). They can still be killed by injury, disease, and malnutrition. But the they don't grow old like we do. If this was the case how would US law and politics change as it became clear to people weren't grow old anymore?

More details: Some back ground on how this all came about. A group of tranhumanist scientist that discovered a magic on and off switch of sorts in our DNA that effects aging. They invented a vires that altered the DNA in the chromosomes but left the rest of the in the human DNA body as it was. They then programed this virus to flip the switch on human ageing. They then dedicated there lives to make sure that every single human on earth was infected. Since those infected show no visible sighs of been sick the vires spreads very quickly. It has no effect on those infected since it only effects the chromosomes on a human and not the rest of the body. But since it the copy of our DNA in chromosomes that is past down to our children the kids of the infected people had the ageing off switch flipped off for every cell in their body.

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    $\begingroup$ A related film: In Time - where nobody ages past 25 but can only live as long as their biologically implanted countdown clock allows them. $\endgroup$
    – adelphus
    Commented May 22, 2016 at 23:00

2 Answers 2


Like many questions phrased this way, the world would change dramatically. You may not even recognize the end result.

Humanity is currently about 7 billion strong. That number is growing at about 1.2% a year right now, and has varied over the years. That is a net growth rate, accounting for a yearly birth rate of 133 million/year and a yearly death rate of 56 million, for a net growth of 77 million/year.

If suddenly we had no deaths, that 77 million would almost double, overnight, to the birth rate of 133 million/year. Every overpopulation issue we have would suddenly double in severity. Food and water shortages would become an even larger issue than they are right now.

Now there's some wiggle room here. You say humans simply don't age. Infections, violent injuries, etc. still kill them. Well, frankly, its reasonably rare to die of old age directly. Its usually either an infection that kills you, or the cumulative sum of a lifetime of injuries that eventually weakens the body until it can go no further. Even if your body might think it's still 25 years old, a 60 year old knee or a 60 year old eye lens suffering from cataracts is still not an enjoyable experience. We're going to have to assume some level of hocus pocus here if we want life to be different after the gene is flipped off. Such hocus pocus could avoid a lot of funny complications, like increased rates of cancer (one of the proposed reasons for the aging process itself is that it is a check against cancerous cells growing out of control).

Handwaving those issues aside, there will be effects which keep the net growth rate down. No society in existence is ready for a sudden doubling of its net growth rate (except perhaps a few "upside down" nations like Japan). That's a huge strain on a society. Conflict for resources would certainly spur great wars, and there's nothing like a war to decrease your excess population!

If you aren't looking for the negative side of things, consider looking at the lives of the incredibly healthy elderly of today. They all share positive messages that you can draw from. Consider the life of Ella Mae Cobert, who recently crushed the record for the 100m dash for the 100 years old and up age bracket, or this 81 year old man who, frankly, is in way better shape than I am! Consider the groups of martial artists from all over the world, who demonstrate their fitness at extraordinary ages, such as Lu Zijian, shown here at 118 years old demonstrating why he is a grandmaster of baguazhang!

Every one of these elderly folk, vibrant and full of life, have a story to tell, and we should feel privileged that they have lived long enough to tell it to us. A story which focuses around ageless humans should certainly learn as much as it can from their real life ageless journey.


There are only a couples ways a mutation could appear in every member of a generation of a species, having not existed at all in the previous generation.

1) Very tiny population bottleneck. Like, Adam and Eve. Even then, Adam and Eve's children should all be different, and a mutation in one would be unlikely to occur in any of the others unless the mutation is actually in one of the parents who is a genetic chimera. Imagine a male's gestational development. It starts with a single cell, and it divides, and its successors divide, and so on. Each division is an opportunity for mutation. So, if on the 12th division or so the piece of "Adam" that will become his testes acquires the longevity mutation, he could pass it on to his descendants while not personally benefiting from it (at least, not body-wide.). Even then, each descendent of Adam's should only have a 50% chance to get it, though there is evidence of some "selfish" genes that somehow turn up in offspring more frequently.

2) Technological genome engineering. This might also require a population bottleneck in order to make it plausible that EVERY member of the next generation receives the gene.

Outside of these possibilities, I don't think there's a believable way around having to deal with a mortal and an immortal class within the same generation.

Note also, conceiving of this as a single gene is very very magically special. If human immortality is even a genomic possibility, it would almost certainly require the cooperation of numerous genes. (Making natural breeding an even more unreliable way of inheriting all the genes contributing to the trait.)

You can see why it's important to understand how this has happened, because if it comes about universally through engineering it looks like the US already needs to be much different than it is now. At present, firstly, it is inconceivable that the "haves" would fund genetic superbabies for the "have-nots." Secondly, if somehow they did fund it, it is unlikely everyone would submit to it.

So, on either the Adam & Eve bottleneck story or the genome engineering story, the US already needs to be very different. And the Adam & Eve story STILL doesn't quite get you there without being slightly fantastical with genes' abilities to improve their chances during allele switching. But you don't have a hard science tag or anything, so imagining a supergene cluster that is super for its own purposes as well as its host organism's isn't so outrageous.

  • $\begingroup$ Yeah this should have been a comment not a answer. Just attacking the premise isn't really an answer. Also you don't know whether the questioner has answers but just isn't sharing them because that doesn't pertain to the question. For all you know the mutation(s) were spread by a retrovirus pandemic, or maybe it's magic, but that doesn't matter what matters is the results not the causes. $\endgroup$ Commented May 22, 2016 at 3:32
  • $\begingroup$ I didn't MERELY attack the premise. I provided what I took to be the nearest plausible scenarios to what the asker was looking for. Also, it would have been like, 7 comments. I could understand the asker taking offense like this (if he were particularly sensitive), but I have great difficulty seeing why you're so hung up. If you can provide a better answer, or even improve mine, I encourage you to do so. $\endgroup$ Commented May 22, 2016 at 3:40
  • $\begingroup$ Note that I don't take your magic suggestions to be a great answer, personally, because the question was asked using only "sciencey" terms. I think my slight situational adjustments are way less damaging to the question as asked than your significant supposition that it's even a magical world... but what the heck do I know. Feel free to write up an answer about it. And downvote mine, while you're at it. $\endgroup$ Commented May 22, 2016 at 3:41
  • $\begingroup$ I see your point let me add some details. $\endgroup$ Commented May 22, 2016 at 3:57
  • $\begingroup$ Viruses are microscopic, and often contagious entities that can spread far enough to force a mutation. Assuming someone created a non-lethal virus that gave every human in the US the required genes, without the consent of the population, then it's entirely possible for this sort of scenario to occur. Of course, there's always just "magic" (as tagged in the question) $\endgroup$
    – TUSF
    Commented May 22, 2016 at 4:03

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