Italian doctor Sergio Canavero plans to put one man's head onto another man's body. He already has the "head " - and plans to put it on a body by 2017.
You may think organ transplants are common procedures - but Sergio Canavero's plans to give a head a new body will be a world first, if it happens.
A Russian computer programmer called Valeri Spiridonov, who suffers from a spinal muscular atrophy condition, Werdnig-Hoffman disease, is expected to donate the head. Werdnig-Hoffman disease is often terminal.
The body will likely belong to a brain-dead individual who is medically alive, but otherwise "dead."
This raises enormous questions.
How do you keep a detached head alive?
Canavero's plans involve cooling the severed head and decapitated body so that the cells can remain without oxygen for as long as possible. Another option, says Dr. Christoph Höhncke, who has successfully transplanted arms, is using machines which continually circulate oxygenated blood through the detached parts of the body. Such machines are used to circulate blood through hearts and lungs during such transplants, for example.
Can a severed spine really be "wired" together?
Very rarely. And are there any chances of a 100 percent return to pre-severed mobility? "Not as far as I know," says Höhncke. When Höhncke and his team of surgeons transplanted two arms onto a man, who had lost his own in a farming accident, they needed to connect four nerves. "The regeneration was not complete. It is never complete. You never know what kind of nerves you're connecting."
Canavero may have a new medical trick up his sleeve, of which the world is unaware. But at this point the Italian surgeon has only said he will use a chemical substance, polyethelene glycol, to encourage the two ends of the spines to grow together.
Assume it works perfectly - what about muscle memory? If my new body belonged to a golfer, am I a golfer now, too?
The brain has to learn that the body is a new one. And the body has to learn that it is being steered by a different brain. All of this has to be learned. This is why rehabilitation takes so long.
So the short answer is: "No."
Can a brain-dead donor really give consent?
Yes, in advance - as with donating organs.
There are also countries that do not require such consent. Canavero has spoken of performing the procedure in China to avoid European laws. He is reportedly learning Chinese in the event he has to stay there.
"Taking advantage of [relaxed legal standards] is a little dubious, for me, from an ethical point of view," says Höhncke.
Who is now the "person?" Who's alive now, legally? Is it the brain? Or is it the body? Who survives, the donor or the recipient?
We don't have an answer to that.
Does the medicine support doing this?
"This is a human experiment. As far as I know, there have only been a few experiments conducted on animals. I'm not sure whether there are enough basic experiments that support this operation."
The first step might be to try this with spinal cord repair - brain transplantation would be the next step. But some like taking two steps at a time.
Could you also put a male head on a female body?
Canavero has said his ultimate goal is immortality. He says wealthy clients have contacted him to ask about the possibilities. Can head transplants lead to immortality?
"When we come to the point where immortality plays a role, then we have a real legal problem - and even more, an ethical problem." Because who decides who lives indefinitely?
Below is a video of Dr. Sergio Canavero himself, explaining the principles of the procedure during a TEDTalk.