Is it possible to breed humans to create a group with no mental or physical deformities. And get to the point where this group of humans is also biologically more resistant to mutations that might cause physical and mental deformities. None of these individuals can have a genetic predisposition to any disease.

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    $\begingroup$ See Eugenics. (Also, don't try it in real life.) $\endgroup$ Commented Jan 18, 2018 at 1:33
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    $\begingroup$ You're going to need to define what genetically perfect means before this question is answerable. $\endgroup$
    – sphennings
    Commented Jan 18, 2018 at 1:38
  • $\begingroup$ Welcome to Worldbuilding, Nathaniel. As sphennigns says, your question doesn't have a definitive answer, because its hard to determine what a mental or physical deformity is. Is there only one perfect human and everyone is just a clone of that person? You need to add information about your desired end-state (all humans can run a sub 10 sec 100 meter dash, all humans can perform integrals in their head, all humans can breathe underwater, whatever). Without that information, your question is 'opinion based' and will probably be closed. $\endgroup$
    – kingledion
    Commented Jan 18, 2018 at 1:41
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    $\begingroup$ What is perfect? My eyes are very light sensitive. Is that imperfect? Some can hear exceptionally well, others cannot, which is perfect? Is skin so fair it burns easily imperfect? Or is skin so black it almost can't be burned imperfect? Are long legs or short legs imperfect? If you're 5'4" are you imperfect? How about 7'1"? What if my eyes aren't quite even? I'm balding, is that imperfect? I'm allergic to almost everything but almost never get colds. Which is imperfect? "Perfect" is so much in the eye of the beholder that the question is pretty much meaningless. $\endgroup$
    – JBH
    Commented Jan 18, 2018 at 1:59
  • $\begingroup$ If you do that, what you'll get is a species perfectly ready to go extinct. Mutations are a feature of sexual reproduction; just because the interim product is half-baked, doesn't mean the final, stable product would be the same. We came from defective chimps after all, the ones that just couldn't compete with the "perfect" ones in their prehistoric lifestyle, so had to do something different. $\endgroup$
    – nzaman
    Commented Jan 18, 2018 at 16:11

2 Answers 2


No, or, not naturally

In a natural environment mutations are all-but guaranteed to happen. This is one of the methods by which evolution occurs, which means that it is baked into our DNA. So it may be possible to reduce/eliminate mutation in humans, but not in a naturally breeding population.

Tight genetic control and embryo manipulation will need to be instituted via artificial means to make this possible.


This runs into the key issue with eugenics (as pointed out in the comments): the definition of a genetically perfect person is subjective.

To put it in more concrete terms, the definition of genetic perfection has evolved considerably in the last...all of human history. Ask a European from 1600 what a perfect person looks like and you are certain to get a different answer than an Egyptian in 2000 BC, or a South American in 1900, or any of us today in 2018.

On the one hand, we like to think that today we know better and have scientific ways of figuring out what genetic traits are better and worse and therefore our decisions will be correct. But...every other person in all of history thought the same thing.

Our definition of "perfect" is always changing. To assume that our perceived perfection of today comes from an objective viewpoint is hubris.

So, no.

Philosophically/morally/historically/sociologically a perfect person does not exist and therefore cannot be made.

Scientifically, in absence of the viewpoints previously mentioned, it is possible, but not while maintaining natural reproduction.

  • $\begingroup$ But if you leave out the subjective "perfect", and just breed for things like increased endurance & disease resistance, or to eliminate obvious genetic defects such as hemophilia, then of course it's possible IF you can get the humans to go along with the breeding program. It's regularly done with other animals and plants. $\endgroup$
    – jamesqf
    Commented Jan 18, 2018 at 3:08
  • $\begingroup$ @jamesqf I disagree. The question refers to exact perfection, implying the complete elimination of genetic defects, diseases, and undesirable traits. Selective breeding can lower the risk of these occurring, but due to the number of generations needed to completely eliminate them new problems are bound to emerge. $\endgroup$
    – enpaul
    Commented Jan 18, 2018 at 3:29
  • $\begingroup$ True enough, but two-letter comments (no) are not possible. Nor, I think, are answers that short. So no, followed by a short explanation of what might be achieved, and how, is the best I can do. $\endgroup$
    – jamesqf
    Commented Jan 19, 2018 at 4:36

No, not really.

It would require redesigning how the genome works. Currently we rely on genetic diversity and redundancy to handle mutations and adaptation. And that pretty much forces the possibility of genetic variability being high enough that it can cause at least some genetic disease. You'd essentially need to create an artificial genome that produces something that appears like a human but really isn't.

Even then preventing mutations would probably be prohibitively expensive. I think that somebody recently argued that such issues are mathematically inevitable for multi-cellular organisms. It was specifically about cancer and had some assumptions I was not entirely happy about but it does give some idea about the level of difficulty one should expect : very high.

And yes, I am basically giving the same answer enpaul did. I hope the rationale is different enough to have value.


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