Scientists have reportedly engineered sheep with organs consisting of up to 15% human cells. A human’s bone marrow stem cells are implanted in a developing sheep ( a fetal lamb), which then develops with the chimeric organs, such as livers, kidneys, etc.
The goal is to make multiple sheeple (I’m adapting this term from a derogatory slang comment for those people who will believe anything) for each patient, for back-ups in case organ donors are ever needed.
The concern with this research has always been the risk of inter-species viral infections that, like HIV and bird flu (actually every flu that we’ve had) will cross species to endanger the lives of many more humans than just the ones that receive the organ transplants.
There’s a huge “yuck factor,” here.