Recently, it was reported that Hiromitsu Nakauchi, a Japanese stem-cell scientist, received government support to create animal embryos that contain human cells and transplant them into surrogate animals: https://www.nature.com/articles/d41586-019-02275-3
In the long run, the advances in the field can result in animals with organs made of human cells that can, eventually, be transplanted into people - an extraordinary alternative to reduce the transplant waiting lists. On the other hand, bioethicists have raised numerous concerns. I was wondering what are the thoughts of my fellow iGEMers: what do you think about the ethical discussions inherent to the field? What are the main challenges that should be overcome to make this technology feasible? How the legislation of your country would react to a similar request?