Scientists have created a rather unusual hybrid...a human and a pig.
Although the embryo was terminated before it could be born, the experiment is still heralded as a pioneering development in organ donor research.
It is hoped that scientists will be able to one day grow functional organs and tissues to be used for transplants, The Independent reported.
The hybrids could also be used for drugs testing, as they would react in the same way as humans do.
The hybrid was created by injecting human stem cells into pig embryos and testing them to see if they could survive. Although it was primarily still a pig, this was considered to be good, as scientists do not want the animals to become too human.
Embryos were planted into sows, allowing them to develop for three to four weeks.
It is claimed this was long enough to see whether they would live but short enough to avoid ethical issues.
The study’s lead investigator Juan Carlos Izpisua Belmonte said: "Our next challenge is to improve efficiency and guide the human cells into forming a particular organ in pigs."