In a move certain to set medical ethicists’ heads spinning, stem-cell researchers in Japan are launching a study with an aim to create hybrid animals out of rats and mice that will produce human organs for medical transplant, according to media reports.

Fertilized eggs of rates and mice, manipulated so they can’t make pancreases, will be created and then injected with specialized human cells. The resulting “human-animal embryos” will be placed in rats or mice, with the goal being human pancreases growing inside the rodents.

The University of Tokyo project is being carried out under the direction of Stanford University geneticist Dr. Hiromitsu Nakauchi. The project was greenlit last month by Japan’s government.

Although about 114,000 people in the U.S. are on waiting lists for life-saving organ transplants, according to the American Transplant Foundation, the U.S. government has declined to provide public funding for similar studies, according to experts.

“A multitude of laws that ban the creation of hybrid beings have been proposed for legislation at both state and federal levels, making such research illegal,” said Alison Rudansky of the Pardalis & Nohavicka law firm in Manhattan. “Scientists argue that legal barriers would halt medically beneficial studies into human modification and medicine for the good of the people.”

Despite the life-saving implications, murky ethical issues abound, she said. 

“These questions are points of ongoing debate in both abortion and animal rights regulations,” Rudansky told Karma. “We can expect that the debate for or against chimera research will follow the same trajectory.”

The Japanese government’s approval breaks new and potentially dangerous ground in several directions. First, prolonged experimentation by scientists hasn’t been allowed and is banned in most countries. In Japan, growth periods had been restricted to 14 days, until March when the country’s education and science ministry issued new guidelines so now embryos can now be brought to term.

Nakauchi’s application to experiment is the first to be approved under the new framework.