They call them Chimeras, pig embreos that have been injected with human stem cells. These creations have been made by various labs around the world but are typically killed before the fetus is able to fully develop.
A research team from the University of California, Davis, is hoping to create Chimeras to solve organ transplant shortages. They will create mutant pigs that lack the genes required to make a pancreas. Then, they hope the human stems cells will fill the void and create a human pancreas within the pig. They believe the process can work for any needed organ.
Although there are many ethical concerns that have delayed research in this area, one of the major concerns is what would happen if a chimera accidentally developed a human brain. How should we treat such a creation? Should we even be allowed to make one in the first place?
Aside from the moral / ethical issues involved, one of the many interesting applications would allow individuals who need a transplant to create their missing organ within a Chimera using their own stem cells. This would create a cloned organ that is a perfect match, in good health, and young – even better quality than a traditional donor organ.