There is a far better way.

Really if the can age an organ form infant to adult in a few weeks then they can just start the clone from a single cell in a similar length of time. Or more realistically just grow an individual organ without anything else. Being able to rapidly grow one organ is easier than rapidly growing an entire body of organs.

But most likely making an organ will proceed like this.

1. A bio-printer prints a non-cellular matrix matching the correct organs extra-cellular matrix complete with signalling proteins. That's not a cell printer BTW but a biological molecule printer.




2. Another machine fills it with un differentiated or partially differentiated stem cells, which respond to the tags forming the correct cellular layout. Ideally this would be a cell printer. likely both machines would be working at the same time with the latter slightly behind the former.




3. differentiating cell produce a working organ likely with some trimming and testing steps before implantation.

The entire process would likely only take a few days and have little waste, we are getting close to this today, I expect to see it in use within the next few decades.

source 1

source 2

Yes With an If, No With a But

Other answers have suggested that live, fast-growing, barely conscious, human infant clones are not worth doing, because there are better methods which are less ethically fraught, better targeted to the required need, and less wasteful of resources.

Speaking practically, however, yes it could be done. But from a story-telling perspective, you might want to explain why it's done this way. You might have to explain that scientific advancement is at this very specific level where they can clone entire humans but [choose to?] not clone individual organs or use donor animals. (I don't know if one is "easier" than the other.)

Let's Do This

Maybe you could say your society is better at other bio-sciences than genetics. E.g., Maybe the "clones" are actually twins, created at the parents' request (or by the State, or by their employer) by splitting the "original" zygote into one or more separate zygotes, and one grows normally while the other(s) is harvested and given the "clone treatment." Maybe the fast-growth is done using synthetic hormones instead of gene-manipulation. Maybe the insensitivity to pain and low brain activity is done by lobotomy on the fetus, or chemically induced partial-coma.

Don't Look Here

On the other hand, your audience might not question the premise. E.g., on Star Trek TNG, Lt. Cmdr. Data cannot use contractions. He just can not. Trekkies ask why but then just figure "Oh it's complicated" and move on (or keep ranting till they die lonely). But if you're going to explore all the dilemmas that arise from your particular type of organ bank, audiences may wonder why we are doing it this way instead of all the other better ways suggested in the other answers.

But you might side-step the sci-fi dilemmas by re-directing attention to more legal and philosophical problems. E.g., is the clone property of the patent holder who invented the cloning process? Why would parents or individuals permit clones or even care? Etc.

But then we're back to where we've started: what issues are highlighted by these clones, which haven't already been explored by androids, replicants, zombies, sentient AI, and yes, clones? I'm not saying there aren't any such issues, I'm just saying that if you're going to set up a highly specific premise, then it should ideally be for a good specific reason. So, from a story telling perspective, it's hard to tell how practical this would be.

The impractical part is that you would need to grow an entire human being (or all the pieces of one in a single unit) just to get one organ.

A patient in need of an organ would either be put in cryo if it's a
critical organ or simply wait a few days to weeks while the organ is
being grown. Once the operation is complete the rest of the organs are
frozen and used for other transplants.

Why grow an organ to order (requiring the patient to wait for days or weeks and possibly die or deteriorate..."cryo" is not foolproof) if you can just pull a ready-made organ out of the freezer instead?

If it's necessary to customize each organ, then who will use the extra frozen ones?

It doesn't make any sense. Either patients use "off the shelf" organs (with perhaps a waiting period for rare histologies) or everyone gets a custom one.

You'd be better off finding a way to grow single organs. Ethically it's a much better alternative (and probably easier than ensuring your "bloated baby" isn't a real person with rights). If not single organs, then perhaps organs in natural groups. Like heart and lungs or kidneys and bladder.

Some yes, some no.

There are alternative pathways laid out below:

If you're going to grow a clone for replacement parts, you need stem cells.

These can be found in one of a few ways:

• Day 2 or 3 after egg fertilization (prior to implantation and cell differentiation), a few cells would be shaved off and preserved. Unless you have some kind of nano-search tech, the egg will be hard to find and get at this stage. Would be tough to do now with a high failure rate of re-implantation.




• The Placenta and umbilicus at birth. We can do this now.




• The epithelial cells (ie cheek cells in the mouth taken by swab) taken from the adult. These will need to be specially treated to bring them back from cheek cells to stem cells (known as induced Pluripotency). We can do this now, the downside is that the cells would be old (think Dolly the sheep, dying of old age before her time). We are working on this and are confident of a manifest solution within a few years.

Then you have a few ways of growing the person/replacement organs.

• Surrogacy, a human accepts an embryo, brings it to term. We can do this now — it takes 9 months, and the baby still has its full brain function. Lobotomy would be required and body maintenance. Presumably an option for the rich. The major organs would not be capable of sustaining adult life until at least two years after birth - kidney function of neonate is 14% of adult's, liver function even less than that, heart too small etc..




• An artificial womb brings the embryo to term, the baby is disconnected and lobotomized. We can't do this, except to reproduce a few cells in a flask.




• Genetic engineering to prevent higher functions from developing, Anencephaly is known, and life support could maybe be provided. We can't produce this condition yet and causes are disputed, give it a few years of research though.




• A scaffold is made/printed (as per other answers, impregnated with appropriate growth factors) then colonized with cells. We can do this now with very simple structures - skin, blood vessels smooth muscle like bladder, single nerves (note: not nerve bundles). We're working on kidneys, pancreas, liver, these are decades away. Heart muscle presents its own problems regarding electrical waves that we've not solved yet.

So as the OP will see, the answer is some yes, some no. The OP is free to figure out how future research will find solutions.