In an extraordinary new development that has huge implications for organ donorship that could save lives, scientists have managed to create the first human donor organ inside the body of a sheep. Scientists hope this could clear a backlog of thousands of patients who wait for a life-saving organ.

Scientists even believe that this could possibly lead to the first human transplant within only five years, a development that could save hundreds of lives each year. Scientists would grow human cells within the body of a sheep to create a viable human organ that could be then implanted within a human body.

With hundereds of people dying on the waiting list each year, this would obviously have a huge impact on the medical community. But there are some significant doubts about whether such organs would be viable and whether the body would reject the implant as soon as it was put in place.

“Even today the best matched organs, except if they come from identical twins, don’t last very long because with time the immune system continuously is attacking them,” said Dr Pablo Ross from the University of California, Davis, according to a Guardian report. “For a pig we typically transfer 50 embryos to one recipient. With the sheep we transfer four embryos to one recipient.”

Ross added that he had some concerns about where the human cells end up in the chimera.

“Let’s say that if our results indicate that the human cells all go to the brain of the animal, then we may never carry this forward,” he said.