In a story that seems to mimic author H.G. Wells' 1896 science fiction novel The Island of Doctor Moreau, human-animal hybrids will be developed as embryos by scientists in Japan after the government gave its approval to the controversial stem-cell research.
The Independent reports human cells will be grown in rat and mouse embryos, then brought to term in a surrogate animal.
This is just a part of the experiments to be conducted by researchers at the University of Tokyo.
Supporters for the project, which is led by renowned geneticist Hiromitsu Nakauchi, say it could be the first step in ultimately growing human organs and transplanting them into people when needed.
Opponents of the research say the scientists are playing God. They fear the human cells could deviate away from the target organs into other parts of the animal. In theory, this could, they argue, effectively create a creature that's part animal, part person.
For this reason, animal-human experimentation has been banned around the world for years.
In Japan, such experiments conducted by scientists going beyond a 14-day growth period were off-limits.
"We don't expect to create human organs immediately, but this allows us to advance our research-based upon the know-how we have gained up to this point," Nakauchi told the Asahi Shimbun newspaper.
He added that he planned to proceed slowly, and will not attempt to bring any hybrid embryos to term for several years.
Nakauchi's caution was welcomed by bioethicists.
"It is good to proceed with caution," Tetsuya Ishii, a science-policy researcher at Hokkaido University in Sapporo, told The Independent. "It will make it possible to have a dialogue with the public, which is feeling anxious and has concerns."