Chimeras are formed when two fertilized eggs or early embryos fuse together with each different population of cells retaining its own characteristics.
Perhaps the most common use is to give human cells to animals in order to form stem cells within those animals that are used to form organs and in those animals that are compatible with humans. They are also a good way for humans to learn more about embryonic development.
The pros are as follows:
- used to create organs for those in need of a transplant
- used to understand the affects of diseases and medicines on humans
- does not require embryonic stem cells
Some cons are a matter of bioethics or religion:
- goes against some religious beliefs
- mistreatment of chimeras
- prevented from fully developing
I believe that the creation of human-animal chimeras is a great outlet for humans to expand our knowledge in the area of human development and others. The idea that we may end up humanizing some animals through our experiments is a risk I believe that we must take. Perhaps risk isn't the right word because I think that humanizing animals would be magnificent. Contrary to what University of Wisconsin bioethicist Alta Charo says, I do believe that we can manage a great ape that has had human embryonic stem cells put in its blastocyst.