Scientists have produced a mouse that has 4% human cells.
It was born in Buffalo, which, in my estimation makes it a 4% American citizen with 4% human rights. It is said to have no human cells in its reproductive system, thus cannot make other mice that are chimeras.
If the researchers cannot respect the rights of the 4% human, they should release it. It has a 4% right to life, liberty, and the pursuit of happiness.
I’m not so sure how ethical it is to create a creature that the only purpose to replace human organs. I’ll ask a similar question that Guinan ask when there was a trial attempting to decide if Data was property or being. Isn’t that like creating a whole race of Datas to use as property/slaves?
Oh, I heard on “a Late Show with Colbert” that someone is using cows with some human cells to help find ways to deal with COVID-19. I also recall having posted a while back about the rather astounding chimeras that have been produced already in the world.
Here is a scholarly article that seem in tune with your ethical concerns.
https://www.bu.edu/writingprogram/journal/past-issues/issue-2/yu/ It concludes with
...To many, chimeras present a threat to our biological uniqueness in the world. In an age when astronomers and cosmologists continue to discover how small and inconsequential we really are, biology stands as the last bastion in defense of our significance and superiority. And this bastion is on the verge of being overrun by surreal part-human animals.
It does seem a bit creepy, but I am not opposed to it. Like I was not opposed to using embryo cells for medical research or even for stem cell treatments.
But, I think there should be limits established and ethical considerations should play a major part.