Exactly what the title says : Could mass human cloning be feasible?
I have a two criteria :
- Clones must come out as adult
- Cloning process must take a maximum of 3 months
Optional : Clones must be cheap to make
There is no scientific reason why cloning would be any faster than normal in-vitro fertilization. Once the egg begins growing, it makes no difference whether it was cloned or fertilized by a parent.
Credit needs to be given to Star Wars here: the reason republic army was built out of clones wasn't their growth rate (though it was described as being twice faster), but rather that they wanted exact copies of the perfect soldier, Jango Fett.
If you want to produce adults in three months, you need high-level genetic engineering to be used to create a completely custom species. It would probably contain considerably less human DNA than most animals, as primates happen to be among the slowest-growing mammals. Three months is on the edge of possibility for depositing enough bone for adult human size, and you'd have to do it very differently.
Given the implications of an ability to completely engineer a sentient species, this would normally put your tech level a notch above that of ST and SW universes. If you want to avoid going so far into the future, you'd need to think of some limitations.
You arent looking for cloning, but 3D printing of living tissue: https://www.sciencedaily.com/releases/2018/02/180201092233.htm
Theres already 3D printed living ears, and the only thing really stopping this process from creating large and intricate organs like a Liver is creating a capilairy system to supply every part of the system with enough blood.
If this system is perfected, you can take someone's DNA (or perhaps custom build DNA from scratch/using advanced CRISPER), grow individual celltypes in large quantities and print a human out of it. Dont expect this to be super fast until you've grown enough stemcells for production and even then the printing is likely going to take a while.
Fair warning though, just like with cloning the brain will still have to learn and create pathways. Even if you print the pathways yourself the brain would only have a fast learning curve in whatever those pathways supply, and getting this print or a normal clone at adult level capabilities would likely require more than 3 months regardless of what you do. Still, if you print the pathways to be similar to that of highly intelligent people like Hawking or Einstein you could cut down on the learning process.