Scientists claim to have created the world’s first human-monkey hybrid in a laboratory in China.
Researchers say they injected human stem cells, which are capable of creating tissue and bone, into a monkey embryo.
The monkey embryo had been genetically modified to deactivate genes that control organ growth.
Scientists say if it had been injected into a female monkey, a human-monkey hybrid could have been born.
It is hoped the research can lead to the creation of human organs for lifesaving transplants.
The project was led by Spanish scientist Juan Carlos Izpisua, who created the world's first human-pig hybrid in 2017.
The team of scientists came from the Salk Institute for Biological Studies in California and the Murcia Catholic University (UCAM) in Spain. The controversial experiment took place in China reportedly to avoid legal issues.
Project collaborator Estrella Nunez, a biologist and vice chancellor of the research team at UCAM, told El Pais: "The results are very promising."
Concerns have been raised over the experiment partly due to fears that human stem cells could migrate to the brain.
Doctor Angel Raya, director of the Barcelona Regenerative Medicine Centre, told the publication: "What happens if the stem cells escape and form human neurons in the brain of the animal? Would it have consciousness? And what happens if these stem cells turn into sperm cells?"
However said that mechanisms were put in place “so that if human cells migrate to the brain, they will self-destruct.” Ms Nunez said.
