[Tossitto]

I've got to wonder about the level of experimentation it takes to get to the point where you can actually effectively create a genuinely braindead, but otherwise wholly functional human unit. From a genetics standpoint, I believe it's a fractaline system, meaning recursive elements, which is (and quite probably wrongly) to say that removing one piece of DNA, or favorably altering it to fit the outcome, could result in unexpected outcomes in the development of other necessary components. Like, there's a good deal of the endocrine system that's tucked away in the brain, delete the PFC and what results? We don't understand consciousness to the degree this demands for a "truly ethical" criterion anyways; and that may be a moot point, as it may be beyond comprehension. And that's discounting a lot of other things. Are organs grown in vitro adapted to actual use? What about epigenetics and possible incompatibilities generated by them? For major endocrine organs, what kind of reaction will the whole have receiving a 1:1 transplant with a 20 year old liver in an 80 year old? And so on...

[Teever]

Nature provides us with a really good platform to develop on: https://en.wikipedia.org/wiki/Anencephaly

If we were to mass grow clones for organs we would probably start with whatever causes this and then add an engineered pituitary gland organioid that is added via surgery to develop the anencephalic clone to maturity for proper organ extraction.

You could even use this to grow bodies for eventual head transplants.

[FooBarBizBazz]

> From a genetics standpoint, I believe [...] removing one piece of DNA, or favorably altering it to fit the outcome, could result in unexpected outcomes in the development of other necessary components.

I wasn't suggesting that gene editing be used to prevent a cerebrum from developing, but merely that an in-utero surgical procedure be used to destroy the cerebrum at some early stage of development. That seems doable. (This whole thing does, however, disturb me.)

> Like, there's a good deal of the endocrine system that's tucked away in the brain, delete the PFC and what results?

That's why I was speculating that the external supply of certain hormones would be required, particularly to get through puberty.

> Are organs grown in vitro adapted to actual use?

Yeah, also a good question.

I was assuming that the technique I was proposing, that of using a whole body -- as different from growing organs in-vitro -- would obviate the worst problems.

(There are still concerns about making sure the body doesn't atrophy, but I think something could be worked out. You can even imagine (again disturbingly) some serious exercise regimen, administered via electrostimulation of the muscles. Or occasional stress to the pulmonary system by injecting adrenaline.)

But in-vitro growth of isolated organs might also be possible. That would immediately skip the worst ethical issues, but it requires more discoveries than the full-body method. We're already getting there for simple organs, though it requires a donor organ to be used as a scaffolding, which is a problem.

> What about epigenetics and possible incompatibilities generated by them?

There must be case studies about organ transplants between twins? Presumably immunosuppressants were not needed?

> what kind of reaction will the whole have receiving a 1:1 transplant with a 20 year old liver in an 80 year old?

What little I've seen, from pop-science releases about experiments with mice, is that some rejuvenation tends to come from that sort of thing.