These advances have made it possible for scientists to create pigs with organs that are more compatible with human biology, thus reducing the chances of rejection. One common edit, for instance, removes a pig’s ability to produce alpha-gal, a sugar that the human body doesn’t make.

Scientists continue to explore ways to improve organ functionality and prevent immune system rejection. If successful, pig organ transplants could one day become a reliable solution for patients in need of life-saving procedures.

Chinese researchers are reporting new steps in the quest for animal-to-human organ transplants. Researchers at Xijing Hospital in China say a pig kidney transplant recipient continues to recover nearly three weeks after that surgery.