It's an old sci-fi/horror staple. People raising clones so they can harvest them for 'spare parts'. In the classic vision, the clones are kept healthy but uneducated until it's their time to be euthanized. Legally not considered humans.
It's a great staple, if you need a story idea that speaks to technology overruling humanity - and let's not forget that what Frankenstein spoke to that same theme.
It's also Never Going To Happen.
There is absolutely no way anyone will ever grow an entire clone body for spare parts.
Instead, in the future, stem cells will be harvested from the person needing the 'spare part'. Some people may bank their stem cells in early adulthood. A 3D printer will be used to make a scaffold and then the stem cells will be encouraged to grow into the new organ, limb, nose, ear, or whatever you need. Need a new heart? Not a problem. Harvest the stem cells and if you can't last out until the new heart is grown, you'll be equipped with a prosthetic for the interim. Amputees will only have to live without the limb for a few months or even weeks while the replacement is grown. As the techniques get better, the replacement organ will be grown without any genetic defects. A perfectly healthy kidney, from your own cells so it cannot be rejected, lacking whatever problems caused you to need it.
Clone harvesting will never happen because it will not be necessary.
How close is this future? How close is a future in which somebody can just order new organs and have them grown in a lab? In which dialysis will be a temporary inconvenience? Surely this will be something for our grandchildren?
Nope. On January 13, a man had a lab-grown trachea installed to replace the one destroyed by cancer. He was not the first (he was the first in the United States). This procedure is approaching routine. Similar techniques have been used to replace damaged ears. Both organs have in common being mostly cartilage.
Scientists have worked out how to use a 3D printed scaffold to regenerate bone. Organs are next. Maybe we will be able to give people new eyes within a couple of years.
A lot of what science fiction has predicted is thus obsolete, including the cyborg who has things replaced because they were lost (as opposed to, say, replacing an eye with a mechanical eye that is better. Still plenty of stories there).
Oh yes, and although we can't replace brains, autograft stem cell research offers opportunities for repairing them...