So I was wondering if new born babies on Mars would have any body changes rather than new born babies in Earth.

Example: Would the bone structure be different when they grow up?

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    $\begingroup$ This is a very good question, but for different reason than implied by you. Developing zygote is initially symmetrical, only later it breaks symmetry and starts developing legs on one side and arms on the other (gross simplification, but you get the idea). If I'm not mistaken, gravity is one of the things that breaks the symmetry, causing proper differentiation. Question is: does gravity of only 1/3 suffice? Is any gravity sufficient, or certain minimal gradient is required? $\endgroup$
    – M i ech
    Commented Apr 2, 2017 at 21:03
  • $\begingroup$ film with the complications of being born on mars en.wikipedia.org/wiki/The_Space_Between_Us_(film) $\endgroup$
    – Eloc
    Commented Apr 2, 2017 at 21:37
  • $\begingroup$ @M.André, you seem pretty new here. Since there are users all around the world, it is wise to wait at least 24 hours before accepting an answer, so that every time zone can bring its contribution. $\endgroup$
    – L.Dutch
    Commented Apr 3, 2017 at 4:37
  • $\begingroup$ Not an answer, since I'm not fully informed, but the harmful effects of radiation both on the egg and in pre-natal development will likely cause a lot of problems. $\endgroup$
    – Mikey
    Commented Apr 3, 2017 at 7:31
  • $\begingroup$ @L.Dutch Thanks i will keep that in mind next time. $\endgroup$
    – M.André
    Commented Apr 3, 2017 at 12:11

4 Answers 4


If you like to read something "deep" about this problem: Kim Stanley Robinson Otherwise:
Will be exactly same as on Earth, but:

Mars has around 38% of Earth's gravity = less muscles need. = Problems when they do actually come back to Earth and experience 263% gravity.
Fluids in our inner ear - may cause disorientation, but most likely only for those, who were born and live in space.
In some time (centuries/millennia) bone structure will change for sure, because those with lighter bones will be higher in 'survival of the fittest'. Because it would make any job on Mars easier for them = more money = children have higher chance to have children. You may not see it now, but will you employ some slow "earth-like" individual, or 200% faster "mars-like" handyman?

In opposite of Fayth85 opinion:
There is still 'survival of the fittest' for example:
"If you solve food problem, ppl won't die and would have one more child"
"If you drive below limit, you won't have problems with law and/or won't have crash"
"If you live to very old age, you can teach children more and give them (most likely) more money. In opposite of you die right after they were born."
"If you win Mars olympic games (because of lighter bones) - your children would have (for sure) the biggest chance to survive"
"If you are attractive - you can be dumb, you still have higher chance to find partner than nonattractive+dumb person."

So yes, but not because baby is born on Mars would make it lighter bones = "magic" - i don't think this thing is already in genes. Maybe in some time human genes would develop into something like: "bigger gravity = bigger bones" but that will take 10000 years at least and frequent traveling between Earth/Mars etc. But I would not underestimate genes.

Source: Mars, Babies in space, Evolution

  • $\begingroup$ I would not trust a source stating that "The International Space Station (ISS) orbits the Earth in a geostationary orbit at a height of about 400 kilometers" $\endgroup$
    – L.Dutch
    Commented Apr 3, 2017 at 7:09
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    $\begingroup$ lol, didn't noticed that. I know about ear problem for a baby born in space, but it is hard to find on internet and i read only that section from that website if it is correct. I also found "an extended stay on Mars sperm count would decrease and fetuses wouldn't be able to properly develop in a space environment", but I don't use information when I heard about it for the first time… and likely it is not true. $\endgroup$
    – Jan Ivan
    Commented Apr 3, 2017 at 7:20
  • $\begingroup$ There's nothing to support your claim that bone density is connected to improved survival fitness. You've totally neglected exogenetic activities, like medicine, which can compensate or eliminate these factors completely. And if evolution is so brutailly selective, why do we still have defects like short-sightedness, and all other genetic diseases and issues, like dwarfism, alcoholism, stupidity, and ugly people. How comee a few centuries/millenia didn't get rid of any of those traits? $\endgroup$
    – Innovine
    Commented Apr 6, 2017 at 9:26

Evolution is a process of seeing what works best in the subject's environment. Though this is a process that takes thousands-to-millions of years, there are times when this process is sped up considerably: a population bottle-neck.

This is when it's easiest to see what little changes are the most beneficial. Then the fastest runner, or the longest runner, or the one that carries the most weight wins out--should any of those traits be seen as desirable to a mate. But you're talking about humans.

Humans no longer follow 'survival of the fittest'. Now it's the one with the cute backside, or the highest intellect. That creates a problem, because if you cannot predict what the 'desirable trait' is, you cannot saw how evolution will pan out. So, I guess it's anyone's guess--but I hope the first part helped somewhat 8-)

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    $\begingroup$ For more information on bottle-necks in population, see 'near mass extinction events'. It's happened a few times already for humans, so there's lots out there to read up on. $\endgroup$
    – Fayth85
    Commented Apr 2, 2017 at 21:42
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    $\begingroup$ The purpose of life is make new life. "The fittest" simply means "those who have most descendants". It does not mean the fastest, the strongest, the cutest or the most intelligent. The fittest are by definition those who have most descendants. Genghis Khan was very very fit... A population bottleneck will greatly increase the importance of genetic drift over natural selection; when a species goes through a population bottleneck fitness is simply a matter of being lucky enough to be among those few survivors. $\endgroup$
    – AlexP
    Commented Apr 2, 2017 at 22:01
  • $\begingroup$ I'd like to point out, in response to Fayth85's answer, that humans actually are still attracted to mates with those characteristics seen as "fit." For example, those things which men find attractive in women (i. e., wide hips, large breasts, etc.) are often useful in childbearing and child rearing, whereas those things women often find attractive in men (i. e. large muscles) would indicate the ability to provide and protect. Traits like intelligence and healthy skin seem to be appealing to both sexes, as these also suggest a higher ability to flourish and reproduce. $\endgroup$ Commented Apr 2, 2017 at 22:27
  • $\begingroup$ @AlexP Agreeing on the 'most offspring' thing. But given the 'pick of the litter' has one or two kids and 'the rest' has kids all over the place? Have you seen Idiocracy? $\endgroup$
    – Fayth85
    Commented Apr 2, 2017 at 22:54
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    $\begingroup$ @C.S.Wright Though I agree, I'm not sure 'attractive' is a term used by all anymore. Let me give you an example. Subject A is a perfect 10. They have sixty potential mates, so they might stand a chance with any of them. So they can take their pick, be as choosy as they like. Now, switch that up. Subject B is a five, maybe a six (you know, where the majority actually is?) how does this affect the potentials pool? How choosy can they be? You're right, the 'hot one' will get laid more, but with birth control? Will that spill over into the next generation? $\endgroup$
    – Fayth85
    Commented Apr 2, 2017 at 22:58

As they grow up, there will be differences in bone density and muscle mass and probably a host of other problems due to the low gravity environment.

But when born, they will be 100% pure human babies, the same as on earth. Things that happen during the organisms lifespan don't influence the next generation... jews have been cutting off foreskins for thousands of years, yet each generation stubbornly gets born with it again.


I disagree with the accepted answer. In the Mars case, the survival of the fittest would have a clearly winner: only those who make past childhood would reproduce. If loss of bone tissue, or harder radiation levels kill a lot of children, or leave them with sort of a glass-bone disease then surely the ones passing on their genes are the ones who can get laid without breaking their hips.

And secondly, maths suggest that mere "survival of the fittest" can't account for the incredible variability that we experience here on Earth. While this darwinian mechanism it's easily proven, evolution must use some other methods as well. Evolution hasn't stopped on humans; [sexual dimorphism][1] is on the wane, as well as our jaws as we don't need that many teeth now (we're getting rid of the third molar).


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