Slouching Toward Chimeras

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Some researchers are speculating about human-chimpanzee chimeras-creating a humanzee. A humanzee would be the ideal laboratory research animal because chimpanzees are so closely related to human beings. Chimps share 98 percent of the human genome and a fully mature chimp has the equivalent mental abilities and consciousness of a four-year-old human child. Fusing a human and chimpanzee embryo-a feat researchers say is quite feasible-could produce a creature so human that questions regarding its moral and legal status would throw 4,000 years of human ethics into utter chaos.

Would such a creature enjoy human rights and protections under the law? For example, it's possible that such a creature could cross the species barrier and mate with a human. Would society allow inter-species conjugation? Would a humanzee have to pass some kind of "humanness" test to win its freedom? Would it be forced into doing menial labor or be used to perform dangerous activities?

The horrific possibilities are mind-boggling. For example, what if human stem cells-the primordial cells that turn into the body's 200 or so cell types-were to be injected into an animal embryo and spread throughout the animal's body into every organ? Some human cells could migrate to the testes and ovaries where they could grow into human sperm and eggs. If two of the chimeric mice were to mate, they could potentially conceive a human embryo. If the human embryo were to be removed and implanted in a human womb, the resulting human baby's biological parents would have been chimeric mice.

Please understand that none of this is science fiction. The American National Academy of Sciences, the country's most august scientific body, issued guidelines for chimeric research on April 25, anticipating a flurry of new experiments in the burgeoning field of human-animal chimeric experimentation. What would be the ramifications of creating hundreds, even thousands, of new life forms that are part human and part other creature? Creatures that could mate, reproduce, and repopulate the Earth?

Bio-ethicists are already clearing the moral path for human-animal chimeric experiments, arguing that once society gets past the revulsion factor, the prospect of new, partially human creatures has much to offer the human race. And, of course, this is exactly the kind of reasoning that has been put forth time and again to justify what is fast becoming a macabre journey into a monstrous Brave New World in which all of nature can be ruthlessly manipulated and reengineered to suit the momentary needs and even whims and caprices of just one species, the Homo sapiens. But now, with human-animal chimeric experiments, we risk even undermining our own species biological integrity in the name of human progress.

With chimeric technology, scientists now have the power to rewrite the evolutionary saga-to sprinkle parts of the Homo sapiens species into the rest of the animal kingdom as well as fuse parts of other species into our own genome and even to create new human subspecies and superspecies. Are we on the cusp of a biological renaissance, as some believe, or sowing the seeds of our own destruction? Perhaps it is time to ask what we mean by progress.