Friday, November 24, 2017

Is a Complete Sex Change Operation Possible?

In one of Lois Bujold's books, a character is changed from female to male via a high tech medical procedure. In Karl Gallagher's Torchship series, sex change operations are treated as routine options–one minor character has changed f to m in order to be physically qualified for a preferred military role and plans to change back later.

That raises an interesting question. Altering the physical structure of the body looks like something that should be practical with the medical technology we can expect to have sometime in the next century. But a complete change should include a change at the genetic level, from XX to XY or the reverse, and Bujold makes that explicit in her story.

This raises two questions. One is whether the change could be made. I think the answer is pretty clearly yes, given a sufficiently advanced technology. One could, after all, have nanotech cell repair machines, very small robot submarines, that go through the body altering every cell.

The more interesting question is to what degree the result would still be the same person. The Y chromosome contains lots of genes in addition to the gene SRY that determines testes development. So replacing an X with a Y or a Y with an X would change a lot of the individual's genetic code. 

Could the problem be avoided by copying all of the genes not relevant to sex determination from the existing Y to the new X? Possibly. But it will not work the other way because the X is much larger than the Y; there is not room on the Y for all the genes from the X. 

Alternatively, is it an issue that doesn't matter because all the relevant determination of the organism by the genes has already happened in the adult? I don't know the answer.

Comments welcome, ideally by people who know more about this stuff than I do.

Incidentally, Gallagher's Torchship series is very good--I have now reread it twice. In addition to being a good action story, it raises issues that I have seen discussed at length in non-fiction contexts, including hostile artificial intelligence and problems with a society where everyone gets a basic income. Particularly impressive for a new author, which I believe Gallagher is.

P.S. My wife, who remembers books much better than I do, points out that in Bujold's A Civil Campaign the sex change operation only results in the male genitals being XY, leaving all other cells XX. The text implies that a complete conversion was possible but would take longer than was available and "the complications can be strange."


Roger said...

To do a complete change, you would have to change a lot more than all X and Y chromosomes. Neurons grow and form connections based on experiences and learning, and those are influenced by years of sex hormonal influences. You would have to separate and reconnect neurons.

You would be reprogramming every cell in the body. This is not going to be technologically possible anytime in the next 1000 years.

Murali Vajapeyam said...

If the technology were feasible, it would be interesting to see a male-to-female transgender falling in love and marrying a female-to-male transgender. Is the latter a lesbian male, and the former a gay female? Those two terms would have been oxymorons a decade ago...

Quentin Langley said...

A related question is when a brain transplant - in reality, a body transplant - will be possible. Your brain could be transplanted into a body of a different sex, or which differed in some other fundamental ways.

Memory is located in the brain. There would be continuity of identity with the prior host of the brain. Presumably the law would recognize the individual as owning the property of the person who provided the brain. This was a big issue in Heinlein's "I will Fear No Evil".

Heinlein's novel includes the unlikely concept of both consciousnesses surviving. In reality we can assume it would only be the brain donor's.

But to what extent would the individual's personality differ? Hormonal balances would be different. This would affect things such as moods, temper, sex drive, and possibly a great deal else.

Bruce said...

If male/female transfers were easy, making yourself more male or female to Betty Boop or Ahnuld levels would be easy. Hotels would offer it overnight.

gurugeorge said...

Another s-f author who played around with the concept of hi-tech, relatively easy and "proper" sex change was John Varley (most of the stories involving his "aliens kicked humans off Earth" scenario have it as part of the background, and a couple of protagonists have spent some time as both sexes).

Aidan said...

"But it will not work the other way because the X is much larger than the Y; there is not room on the Y for all the genes from the X." Perhaps but it might not matter because one of the X's in a female is silenced in every single cell anyways, so maybe you wouldn't need to copy anything over. However, from my limited understanding, the particular X-chromosome that is inactivated in a female can be different in each cell .

But this sort of sex change would be massively more complex than swapping an X for a Y or vice versa. Not only are some X-chromosomes inactivated, but many genes themselves (on all chromosomes) are inactivated through epigenetic control etc. So you'd have to figure out which particular genes on the sex chromosomes should be or should not be accessible for expression. This would vary in every single cell type.