There have been cases where a person has had one of their brain hemispheres removed, and they ended up living a fairly normal life. Could it be possible to split a normal person down the middle and create two people, each with a brain hemisphere? Machines could be used to replace organs that can't be split, like the heart.

I'm assuming there would exist some very advanced technology to prevent excessive blood loss and other problems with splitting a person down the middle.


2 Answers 2


If you split a human early enough (in the first weeks after fertilization), you can get monozygotic twins.

Other than that, you are in the field of science fiction and we cannot safely answer such question on a science website. I am not sure your question will be accepted in its current format but you may try WorldBuilding.SE.

And if you like fantasy novels, I recommend The Cloven Viscount by Italo Calving! You will definitely not learn much about biology in this book though.


Given how some parts of the brain control the opposite hemisphere of the body, and how this is not consistent throughout the entire brain, you would have to do a lot more than split someone in half down the middle.

Importantly, in split-brain patients only the cerebral cortex is hemisected, and only at a particular (though significant) point of connection, called the corpus callosum. It would not be possible to do this through the entire brain.

Especially in adult humans, some functions become lateralized, as well, so each "person" would be capable of different functions.

  • $\begingroup$ I see, the hemispheres would need to be swapped after separating them so a hemisphere stays with the side of the body it controls. $\endgroup$
    – Thomas
    Commented Jul 22, 2017 at 3:45
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    $\begingroup$ @Thomas It's not possible to separate in that way. Things are too intertwined. You can refer to it as a sci-fi possibility, but in the real world it isn't even close, not even with the most expert surgeons or even futuristic robotic abilities. $\endgroup$
    – Bryan Krause
    Commented Jul 22, 2017 at 3:48
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    $\begingroup$ In split-brain patients, only corpus callosum is hemissected because its the only point where thetwo hemispheres connect. IMO spliiting hindbrain into hemispheres wouldn't be very logical... $\endgroup$ Commented Jul 22, 2017 at 13:40
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    $\begingroup$ @another'Homosapien' That's actually not true - there are the anterior and posterior commissures, and there are some other indirect pathways between cerebral hemispheres. The corpus callosum is just the bulk of the connectivity. But yes, there is no sense in splitting the hindbrain, nor parts of the midbrain. $\endgroup$
    – Bryan Krause
    Commented Jul 22, 2017 at 15:24
  • $\begingroup$ Although there have actually been some cases where a human have survived with half-a-brain after one hemisphere was surgically removed - the remaining hemisphere took up the slack. mentalfloss.com/article/70120/… $\endgroup$ Commented Jul 23, 2017 at 0:30

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