Spanish scientists have become successful in developing first human-monkey chimera embryo in a bid to harvest human organs for transplantation, a leaked research has claimed.

Chimera is such an organism who have cells of two or more species.

The team of researchers from the Salk Institute in the US and the Murcia Catholic University in Spain had to come to China for the study as the Spanish government did not allow to conduct the controversial research, which has sparked an ethical debate.

Lead scientist Juan Carlos Izpisúa Belmonte has earlier been involved in an study to create a pig-human embryo.

The researchers genetically modified monkey embryos to deactivate the genes which are used in the formation of organs. Then, human stem cells were injected into the embryo.

A member of the team told the Spanish newspaper El Pais that “the results are very promising.” He said the experiment was essential towards developing human organs in animals.

Details of the research have not been made public though. But “scientists believe organs genetically matched to a particular human recipient could one day be grown inside animals. The approach is based on taking cells from an adult human and reprogramming them to become stem cells, which can give rise to any type of cell in the body. They are then introduced into the embryo of another species,” the Irish Times reported.

The new study has raised questions such as what would happen if stem cells formed human neurons in the monkey’s brain and what if the cells turned into sperm cells. “Would the monkey have consciousness?”