As I'm sure you're all aware, human beings at some point in their lives -- generally post-puberty or so -- stop growing. As a result, there's some easily-predictable measures, such as the average height of a human, and some pretty consistent standards in our society, such as the height of a typical door or a ceiling.

This, however, relies on some sort of bizarre internal biological mechanism that basically, at some arbitrary point in our development, says "Okay, we're done growing." And while there are a few examples of genetic abnormalities where that mechanism fails, by and large that's a constant across virtually all life on our planet.

But what if it weren't?

What if this biological mechanism simply had never existed? Clearly there are some upper-bounds on physical size due to the infamous Square-Cube Law -- such as reaching the point where our bones fail under our own weight, or where our heart simply can't keep up with the vastness of our circulatory system -- which would likely take the place of generic "old age" as putting in place the upper limit on how old we could get. But what would be the more subtle impacts on our biology? And how would this change the face of our society?

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    $\begingroup$ You die at 22 from heart failure. $\endgroup$ Mar 18, 2015 at 21:59
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    $\begingroup$ @SerbanTanasa It looks like Wadlow was not just growing without signs of stopping, but growing faster than normal humans as well. I'd expect someone without the increased rate of growth could survive well past the age of 22. $\endgroup$
    – Kromey
    Mar 18, 2015 at 22:32
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    $\begingroup$ Something similar on xkcd. $\endgroup$
    – Samuel
    Mar 19, 2015 at 0:31
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    $\begingroup$ As many of my elders have reminded me, we never stop growing; we just start growing horizontally instead of vertically. $\endgroup$ Mar 19, 2015 at 19:43
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    $\begingroup$ I would point out that the biological systems that control growth are anything but arbitrary $\endgroup$
    – James
    Mar 20, 2015 at 4:32

4 Answers 4


The square cube law is the biggest impact already. Humans are already nearly as big as we can be before we get to suffer, already the tallest humans have major health issues. If we continued to grow at the rate we did through puberty we would reach a point of pain and easy injury in only a few additional years, and death not long after that. It's not old age if it happens shortly after adulthood even begins!

You would have to either have us grow much slower or have the rate of growth cut back drastically after puberty to have anything remotely like a normal life span.

Similarly by the time that anyone is significantly large enough to have any impact beyond needing slightly taller doors we would have reached the point where our size is causing pain and easy injury, at the very least. The square cube law comes into play so rapidly that, unless it is hand waved away, you can't do anything interesting with humans that continue growing before they are too weak to be interesting.


You've already mentioned door and ceiling heights - these would have to be higher than the oldest (and therefore tallest) people. Depending on how tall we could actually grow before the same fate as that that overtook Robert Waldow overtakes us all you might have buildings that are two or even three times taller per floor than current buildings. This would mean that there'd have to be more skyscrapers per city to house the same number of people as we have now as the overall heights of buildings wouldn't be higher than it is for our buildings.

There'd be impacts on other technology like cars and aeroplanes. These would have to be larger. With aeroplanes it could be that people over a certain age can't fly as they simply can't fit inside the craft. This could have had a serious impact on the development of flight. Engineers with the skills necessary to invent aircraft could be too large to build a craft capable of lifting them off the ground. This could have delayed or even stopped us flying.


Several points come to mind:

  • Food - you would need an ever increasing amount of food to sustain and fuel growth of the body. A bigger stress on food production worldwide.

  • Buildings - not just doors and ceilings, but think about accommodating a drastically wider range of different sized people. If a big family were to live together, the room and furniture sizes would also have to pertain to each member. It is hard to imagine everybody sitting at the same dinner table. Rooms and furniture for grandparents would have to be enormous compared to the childrens' room.

  • Similar for transport and everyday items. You would not only grow-out of your clothes, but also your car, bicycle, sports gear... Creating even bigger stress on economy and increasing recycling

  • Public venues - imagine building a cinema that can comfortably seat everybody - with a chair not too big and not too small... Also taking into account that you wouldn't want a huge grandpa sitting in front of you...

  • All in all - the world would be drastically different - the society, economy and politics would be more segmented according to age (size)...

  • $\begingroup$ And then the bears ate Goldilocks for trespassing, welcome to the site @Harijs $\endgroup$
    – James
    Mar 20, 2015 at 4:34

As the Wadlow case shows fast continuous growth equals faster death. Unless...


The average human lifespan would shrink, a lot. Doctors would probably find a way to create artificially the puberty gland thing. (I can't find it but it basically regulates body growth.) But before they're done our population has shrunk a lot. By the time the Growth Regulation Device (GRD) is cheap enough for the masses most of us will be people who have less need for it. (People who are genetically predisposition to be shorter. Like myself...)


Alright. Now it gets interesting. Using the GRD humans allow themselves to grow for a year or to when they turn (40?). At 40 your cells stop regenerating. However because you grow your body heals up a bit. In the end this could help extends human lifespan dramatically.


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