Beating a Dead Centaur


There is currently much debate over the ethics of chimeras — organisms that are partially one species and partially another. This debate is especially heated when humans are one of the species involved. Nature has published an editorial on the controversy. I don’t intend to comment on the position of the editorial, but rather on the sloppy use of language by the unattributed author.

I don’t know enough about the research and clinical applications of chimeras involving humans to make any claims about the ethics of such creations, but I do know enough about biology to get all hot under the collar when I see a sentence like this:

Under what circumstances should the fusion of cells of animals and humans be permitted?

Or this:

The new proposals provide a well-reasoned and permissive approach to the contentious issue of the nuclear transfer of human nuclei to a human donor egg for the purposes of therapeutic cloning, and also propose that other research combining animal and human materials should be subject to more stringent licensing procedures.

And this:

The document recognizes that human-animal fusion products have been widely used in biomedical research for many years.

Or how about this:

In the United States, the National Institutes of Health does not fund research involving the transplantation of human embryonic stem cells into animal embryos. In Canada, this funding restriction extends to the transplantation of human tissue-specific (or ‘adult’) stem cells to animal embryos.

Notice the trend? They all perpetuate the false dichotomy between humans and animals. Once again, I could care less — at least for the sake of this blog — about whether chimeras involving humans are ethical. What bothers me is the concept that these are human/animal chimeras.

It’s not like the author can’t get it right. Here’s an example of the proper terminology:

In 2005, the US National Academy of Sciences stated its opposition to research in which human embryonic stem cells are introduced into non-human primate blastocysts.

It’s “humans and non-humans” not “humans and animals”. And here’s another example of proper terminology, this time when we’re talking specifically about primates:

Another important line of investigation is the engraftment of human stem cells into non-human primate models.

Beautifully done. Because humans are both animals and primates, it makes no sense to write about “human/animal chimeras” or “human/primate chimeras”. I wish the author of the editorial had taken note of the terminology from the one cited article:

Human/nonhuman stem cell chimeras will be increasingly applied to study human cells in developing nonhuman animals. Such experiments raise a number of issues that may create further controversy in the stem cell field. Here we outline the scientific value and ethical ramifications of such studies, and suggest how such experiments may be conducted ethically.

The cited Nature Medicine article executes a nearly flawless use of the human/nonhuman terminology. If only the Nature editorial hadn’t been so sloppy.

And, as an added bonus, I present a passage displaying the chimeric property of half proper terminology and half crappy terminology:

At present, such guidelines are reasonable but do not consider several promising and arguably necessary avenues of research that combine human cells or cellular components with other species. These include combining the genetic material of humans and other species, the prenatal combination of cells from different individuals (animal to human, human to animal, or human to human), or grafting tissue from humans to animals.

To recap: “humans and nonhumans” or “humans and other species” is a-ok. Just don’t write about humans and animals.


  1. #1 Roy
    January 6, 2007

    I think it helps to see the insistence on human-versus-animal as an example of elective delusion. They know better, but they don’t like what they know — that humans are animals — so they change what they know by pretending to know what they wished were true, that humans are categorically distinct from animals.

    Maintaining the delusion takes constant vigilance because there are countless reminders that humans are like animals, and animals (especially the social ones) are like humans. Just think of the parasites which find humans and other species as natural hosts. The deluded get disturbed when they run into moral behavior exhibited by other species, and are quick to dismiss obvious acts of kindness and concern as dumb animal instincts.

    I had a Doberman who’d never seen a mirror. A woman had me bring him into her bedroom so she could close the door and set him up to encounter a mirror so he would act like a typical stupid beast and bark at it. Instead, he rushed the image, saw that it mimicked his motion, and recognized it was his own image. He turned to look himself over, admiring his build. The woman who’d set this up then said, “Men, they’re so vain.” She dismissed his self-awareness and obvious intelligence. Why? Because their existence offended her.

  2. #2 Jonathan Badger
    January 6, 2007

    Do you get upset when the local animal hospital refuses to treat you? “Look, doctor, I’m clearly a eukaryote who is not a plant, fungus or protist!”

  3. #3 RPM
    January 6, 2007

    there are countless reminders that humans are like animals

    That’s because humans are animals.

    Do you get upset when the local animal hospital refuses to treat you?

    I don’t ask a veterinarian to treat me because I can go to a doctor who specialize in my particular species. Although I’d expect a vet to be able to treat me as well as they would treat any other mammal that they don’t see on a regular basis (a squirrel, perhaps?).

  4. #4 radar pangaean
    January 7, 2007

    I run into this frequently with my wife. She’s a fundamntalist-type Christian. It’s apparent that the dotrine of her church(es) firmly reject the biological fact that homo sapiens is just another species of animals.

    We’ve reduced this ‘disagreement’ to a lmited short-hand within any discussions we have:

    Me: “as with other primates, the human animal exhibits this characteristic.”

    Her: “people are not animals”.

    Me: “Objection noted… as i was saying …” at which point i pick up where i left off.