Medical experts have condemned the US government for its plans to lift a ban on some controversial biomedical research, raising fears that it could lead to part-human, part-animal embryo development.

Sounding like something from a budget sci-fi flick, the new policy would allow for Frankenstein-style experiments that take human stem cells to create hybrid embryos with those of animals, known as chimeras.


The government's National Institutes of Health (NIH) discussed reasons behind the proposed lift via a blog post by its Associate Director for Science Policy, Carrie Wolinetz.

In the post, Wolinetz outlined a new policy to permit scientists to get federal money to develop chimeras, under certain carefully monitored conditions.

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But the news has worried some medical experts, who believe the research is unethical, and could spiral out of control; that 'playing God' with biology could one day lead to "adverse consequences", such as the creation of animals with partly human brains, perhaps giving them some semblance of human consciousness or human thinking abilities.

Another concern is that the cells could develop into animals with human sperm and eggs and breed, producing human embryos or foetuses inside animals or other hybrid creatures.


Currently, the 2009 NIH Guidelines for Human Stem Cell Research prohibit introducing human cells into nonhuman primate blastocysts and the breeding of animals. But the NIH argues the embryos provide invaluable tools for medical research and would take the necessary steps to prevent such extreme outcomes.

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The scientists in favour of lifting the ban hope to use the embryos to create animal models of human diseases, which could lead to new ways to prevent and treat illnesses. Researchers also hope to produce sheep, pigs and cows with human hearts, kidneys, livers, pancreases and possibly other organs that could be used for transplants into humans.

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"I am confident that these proposed changes will enable the NIH research community to move this promising area of science forward in a responsible manner," Wolinetz wrote in a blog post.


"At the end of the day, we want to make sure this research progresses because its very important to our understanding of disease. It's important to our mission to improve human health," she said in an interview with NPR. "But we also want to make sure there's an extra set of eyes on these projects because they do have this ethical set of concerns associated with them."

The biomedical research behind this type of study is by no means a brand new thing. Scientists have created and used animal models containing human cells for decades to gain valuable insights into human biology and disease development.

Take for instance human tumour cells are routinely grown in mice to study cancer disease processes and to evaluate potential treatment strategies. To advance regenerative medicine, it's common practice to validate the potency of pluripotent human cells – which can become any tissue in the body – through introducing them into rodents.

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But that hasn't stopped other medical experts in the field condemning the whole thing. Physician, Theresa Pham, said the research "crosses the ethical line".

"As a physician who is in the field of research, I feel strongly that this use of chimera crosses an ethical line ... advancing our knowledge in some areas of science can't and should not be approached with the same presumptuous naiveté," she said.

"If the predictions are wrong and the safeguards are not enough, then the price will be the cost of our humanity as well as these new lifeforms that did not ask to participate in this frightening enterprise."


However, not all professionals in the field are against the lifting of the ban.

According to Nature.com, Steven Goldman, a neuroscientist at the University of Rochester in New York, said the 2015 moratorium was overkill and is relieved it will now be lifted because the new guidelines are "more intelligent from the standpoint of where the science is".

The NIH's rule for lifting the ban is now open for public comment for 30 days, after which the agency will issue a final rule and lift it. Wolinetz hopes that this will be ready in time for the grant cycle that begins in January 2017.