Though the idea may bring up visions of Doctor Moreau, the NIH proposal to allow creation of part-human part-animal embryos isn’t about creating a race of animal men, but providing opportunities for better medical research.
The National Institutes of Health is proposing a new policy to permit scientists to get federal money to make embryos, known as chimeras, under certain carefully monitored conditions.
… scientists 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.
Currently, animals are less than perfect—often a lot less—when it comes to acting as models of human organs and organ systems. And the possibility of being able to grow transplantable organs could not only greatly expand the availability of such organs, but actually produce organs that require much less anti-rejection drugs than those from human sources.
The NIH imposed a moratorium on funding these experiments in September because they could raise ethical concerns.
One issue is that scientists might inadvertently create animals that have partly human brains, endowing them with some semblance of human consciousness or human thinking abilities. Another is that they could develop into animals with human sperm and eggs and breed, producing human embryos or fetuses inside animals or hybrid creatures.
The proposal to drop the moratorium comes with guidelines to address these concerns, but of course the whole concept of creating animals for testing purposes comes with its own set of ethical considerations, no matter what the genetic sources.
These embryos would not actually be hybrids in the sense that they were a genetic cross between humans and animals. Instead, they would be made by inserting human stem cells into already-developing animal embryos. So the tissue within the animals would be either fully human or fully animal. Animals containing cells with different genetic origins are generally referred to as chimeras.
However, in addition to the stem-cell-based chimeras, the NIH would also consider hybrid organisms which have been banned to this point.
… the NIH would even consider experiments that could create animals with human sperm and human eggs since they may be useful for studying human development and infertility. But in that case steps would have to be taken to prevent the animals from breeding.
That idea, of having true human-animal hybrids that would be allowed to develop beyond the embryo stage, brings a whole new set of ethical concerns … and not a small amount of disquiet.
A committee would review proposals and approve or deny use of the technology.
That committee would, for example, consider experiments designed to create animals with human brain cells or human brain tissue. Scientists might want to create them to study neurological conditions such as Alzheimer's and Parkinson's diseases. But the experiments would undergo intensive scrutiny if there's any chance there might be a "substantial contribution" or "substantial functional modification" to an animal's brain.
Medical researchers are excited about the ability to gain a better understanding of disease mechanisms, drug effects, and the progress of conditions. That, plus the possibility of greatly expanding the availability of transplant organs—possibly using the patient’s own stem cells as a source—holds out the possibility that lifting this ban could save many thousands of lives. A chronic shortage of transplantable organs means that not only do many patients die each year waiting for an organ to become available, but patients that are outside of certain age ranges or have other complications are never even considered for transplant.
A 30-day comment period will be held before the new policy is implemented.