Crossing Species Boundaries and Making Human-Nonhuman Hybirds: Moral and Legal Ramifications

People often react with horror, disgust, or simply indifference when asked about the advisability of creating part-human, part-nonhuman chimeras. Few people will express a positive feeling about this. Ingrained in people's minds is the idea that birds, animals, or fish are creatures created by God to be separate and distinct from human beings and should remain as such. Although hybrids among closely related animals are known (e.g., mules) and certainly plant hybrids are well-known, somehow crossing the so-called evolutionary barrier through scientific interventions does not resonate well with most people; it is considered an overreach for scientists to play God. This then becomes a highly emotional issue when one talks about creating artificial human-nonhuman animal hybrids without clearly defining the nature of the hybrids or the purpose of creating them.

In their thought-provoking article "Crossing Species Boundaries," Jason Scott Robert and Françoise Baylis (2003) critically examine why this is so. Why do people think that species identity is fixed by nature? Why should natural separation be maintained and the boundaries not be breached? They argue convincingly that the biological species concept is flawed and that there are enough variations for a strict definition of species to be meaningless. If species cannot be defined, then the fear of crossing the evolutionary boundary is irrational. They point out from the genome sequences that there is a variable but identifiable relatedness between the nucleotide sequences of Homo sapiens and other animals, worms, flies, and so on, including plants. They argue that there is no unique DNA sequence in the human genome, as far as is known, that points to the uniqueness of Homo sapiens as compared to the rest of the animal world. Indeed, the DNA sequence identity between chimpanzees and human beings is very high, between 98.4 and 98.8%, close to the 99.9% identity among human beings. Yet, people will be loath to accept a chimpanzee as akin to a human being, their gentle nature and above-average intelligence notwithstanding!

So, what's so unique about human beings? Robert and Baylis consider the often promoted argument that language skill is unique to human beings. They point out, however, that not all human beings speak or write a language and that, although we don't necessarily understand what they say, dolphins do many things when instructed, thus showing a high level of communication skill. I remember that as a child I used to visit the home of my sister, who had a parrot that I always thought was kind of stupid. Whenever I would enter my sister's home, the parrot would start "Here comes the jerk! Here comes the jerk." I think he was coached by my nephew; nevertheless, I believed strongly that all birds in general, and parrots in particular, had no intelligence or language skills and were particularly deficient in recognizing super-intelligent human beings! But they did speak a human language!

Having found no rational reason why there should be any ethical debate about the prospect of crossing species boundaries between human and nonhuman animals, Robert and Baylis conclude that part of the reason for people's repugnance to accept such hybrids is because they are thought to be unnatural, perverse, offensive, or frightening. People also believe that they have moral reasons not to accept human-animal hybrids, as they would certainly perform roles different from the known societal roles animals normally hold, such as being sources of food, performers of hard labor, transports, objects of hunting, and so on. Whatever the reasons, Robert and Baylis find them to be largely unsatisfactory and conclude that there is much to debate about the scientific, political, and moral imperatives that will govern future endeavors in making human-animal hybrids.

While Robert and Baylis deal with the moral and philosophical...