The combination of humans with animals has been a concern since the Old Testament.1 It has been of particular concern in recent years because of advances in genetic manipulation, in vitro fertilization, and cloning techniques which make laboratory human-animal combinations easier to create.
Many animal research models containing human genes have been created by scientists over the last couple decades. For example, the "OncoMouse," a transgenic mouse exhibiting a human cancer gene, was patented in 1988 by Harvard researchers and is used for cancer research.2 One would presume that at some point, human/nonhuman transgenic organisms with enough "humaneness" would be considered human enough to be accorded a certain level of human dignity. Such organisms which possess a particularly human phenotype or exhibit certain human behaviors would seem to be worthy of increased respect.
Some, however, would deem human/animal organisms a lower order of being which would not be worthy of full respect or dignified treatment. One educator/theologian has written with enthusiasm about creating human/nonhuman chimeras, so they could perform societal drudge-work:
Chimeras or parahumans might legitimately be fashioned to do dangerous or demeaning jobs. As it is now, low-grade work is shoved off on moronic ... individuals, the victims of uncontrolled reproduction. Should we not "program" such workers thoughtfully instead of accidentally, by means of hybridization?3
Some activists are taking it into their own hands to prevent the creation of human/animal chimeras. In 1997 biologist Stuart Newman and economist/biotech critic Jeremy Rifkin submitted a patent application for certain chimeras including a "humouse" and a "humanzee."4 Their aim was not to actually create the chimeras; rather, they wanted to hold the twenty-year patent on such research in order to keep others from attempting to create and patent such creations.5 The patent office has rejected their application four times. Each time, Newman's lawyers have been able to argue it back to life.6 One continuing objection by the patent office is that the chimera would be too "human." The Thirteenth Amendment against slavery means that no human being can be owned (thus no human being can be patented). Newman's case is still officially pending.
Dr. Leon Kass, chairman of the President's Council on Bioethics, has written of the "wisdom of repugnance" in e analyzing human cloning: "Revulsion is not an argument ... in crucial cases, however, repugnance is the emotional e expression of deep wisdom, beyond reason's power fully to articulate it.... Shallow are the souls that have forgotten how to shudder."7 Perhaps such is also the case with instinctual repugnance at human/animal combinations. The council recently published Reproduction and Responsibility, in which it advises prohibiting "the production of a hybrid human-animal embryo, by fertilization of human egg by animal sperm or of animal egg by human sperm," or the transferring of a "human embryo into the body of any member of a nonhuman species." The report states emphatically that "an ex vivo human embryo ... belongs only in a human uterus."8
The Pontifical Academy for Life, in Prospects for Xenotransplantation (which can be used for guidance since it considers the related issue of interspecies organ/tissue transplantation), considers any change in "personal identity" - to be a major criterion to consider in analyzing the morality of interspecies transplants:
in general, the implantation of a foreign organ into a human body finds an ethical limit in the degree of change that it may entail in the identity of the person who receives it.9
For example, xenotransplantation of monkey hearts and kidneys into humans has been done numerous times since 196310 and is considered morally legitimate because it is generally acknowledged that this does not change individual identity. However, some organs in the human body, "such as the encephalon [brain] and the gonads [ovaries or testes], are indissolubly linked with the personal identity of the subject because of their specific function."11 Thus Prospects states that human/animal interspecies transplants of; brains or gonads (for the purposes of procreational transmission of identity) cannot be morally licit.12
It should be noted that there are also some genes which could be inserted interspecies that would change an organism's identity, and others that would not. Likewise, there is a difference between interspecies transplantation when the recipient is an adult versus inserting cells at the embryonic/fetal stage. With the latter comes the real possibility of alteration of the individual's identity. Animal experiments have shown that because of the highly plastic nature of the cells at this stage of life and because the architecture of the body (including the brain) is still in development, an introduced cell and its progeny can be incorporated into the embryo in a seemingly random fashion.13 One cannot say with certainty if the chimeric individual's identity has been significantly clanged, but the likelihood is that it has been, due to the highly formative time frame of introduction.
There have been a couple of types of human/animal interspecies experiments published recently. One type is the growing of human cells in immature animals, which essentially creates a chimeric organism. One group injected human adult bone-marrow stem cells into fetal sheep. They found that the cells were distributed throughout the sheep's body and differentiated into human blood, liver, skin,14 and heart.15 Another group injected human adult bone-marrow stem cells into fetal pigs and found human cells throughout the pigs' blood. Fused pig-human cell-hybrids were also found in the epithelium.16 Another group discovered that human umbilical-cord blood cells injected into the liver of immunodeficient newborn mice led to development of human immunological cells and lymph nodes.17 None of these studies mentioned that human cells differentiated into brain cells or human gametes in the animals, both of which could be considered ethically problematic. However, it could be that the brains and gonads were simply not dissected for this information.
Another type of recent interspecies experiment is the creation of human-nonhuman embryos via cloning techniques: insertion of human somatic cells into enucleated animal oocytes. The biotech company Advanced Cell Technology inserted human somatic cells into enucleated cow oocytes to produce human stem cells.18 Chinese researchers did the same, using rabbit oocytes.19 Renegade "researcher" P. Zavos inserted human granulosa cells into enucleated cow oocytes to "practice" his human cloning techniques.20 All of these are ethically problematic, at least partly due to the interaction that can occur between the animal mitochondrial DNA and the human nuclear DNA within the embryo. In addition, these embryos were created with the intention to kill them later, for their stem cells or to preclude further growth.
Significantly changing the identity of an organism via combining human and nonhuman cellular or genetic material (especially at the embryonic or fetal level) could be construed as a violation of the dignity of the human person. John Paul II, in his "Theology of the Body," uses the term "original solitude" to refer to the human condition of man, including his distinctness from the animals.21 Genesis 2:19 states that "the Lord God formed out of the ground various wild animals and various birds of the air, and he brought them to the man to see what he would call them."
John Paul II describes this as a "test" and a way for man to understand his place in creation better:
The first meaning of man's original solitude is defined on the basis of a specific test or examination which man undergoes before God (and in a certain way also before himself). By means of this test, man becomes aware of his own superiority, that is, that he cannot be considered on the same footing as any other species of living beings on the earth.22
By naming the animals, man sees what he "is not," and he asserts himself as a person, with subjectivity, consciousness, and rationality. Man's body also has significance here: Adam's body makes evident to him that he is different from the animals.23
Man was also made in the image of God.24 Interestingly, in the biblical description,
man's creation is essentially distinguished from God's preceding works. Not only is it preceded by a solemn introduction [',Let us make man in our image, after our likeness"], as if it were a case of God deliberating before this important act, but above all, man's exceptional dignity is set out in relief by the '1ikeness" to God of whom he is the image.25
The dramatic way in which man is created highlights man's incomparable dignity.
The Old Testament has strong proscriptions against sexual relations with animals.26 The injunctions were so strong that death was the punishment for transgression. There were also proscriptions against various forms of incest.27 The incest regulations, besides helping keep societal peace, also likely kept the Israelites genetically healthy, because inbreeding can lead to increased congenital abnormalities and certain genetically linked diseases in the population. Similarly, perhaps the antibestiality regulations served to keep the human (i.e., the imago Dei) separate from the nonhuman (the non-imago Dei) with regards to procreation and potential genetic crossing. One could venture that God not only abhors the unspeakable act of sexual relations between animals and humans, but also the combining of their genetic constitutions at a certain level.
Finally, the Incarnation speaks to us of the dignity of being human and of the human body. Jesus Christ did not come as an animal, but specifically as a human being, in a human body. This bespeaks the dignity which God accords human beings and their bodies and how specially He views the human race. It thus seems to lead towards the blasphemous to purposefully combine the genetic or bodily material of a human being and an animal in a way that changes either of their identities. To mix the imago Dei with non-imago-Dei seems a violation, and evokes a certain repugnance. Perhaps this repugnance is a sign of wisdom.
1 See Ex 22:18, Dt 27:21, Lv 20:15-16, and Lv 18:23 ("You shall not have carnal relations with an animal, defiling yourself with it"). All individual scriptural quotes are from the New American Bible, St. Joseph Edition (New York: Catholic Book Publishing Co., 1992). [Back]
2 Dashka Slater, "Humousebn," Legal Affairs (November/December 2002); and Mark Dowie, "Gods and Monsters: TaLking Apes, Flying Pigs, Superhumans with Armadillo Attributes, and Other Strange Considerations of Dr. Stuart Newman's fight to Patent a Human/Animal Chimera," Mother Jones (January-February 2004), http://www.motherjones.com/news/feature/2004/01/12_401.html. [Back]
3 Joseph Fletcher, The Ethics of Genetic Control: Ending Reproductive Roulette (New York: Anchor Press/Doubleday, 1974), 173. Also, a recent science fiction book called Chimera, reflects this speculation. It features a Blade-Runner-type future in which human/animal chimeras are bred to work for humans: catwomen as prostitutes and dog-men as hired thugs. Will Shetterly, Chimera (New York: Tor Books, 2000). If such a future were ever to come about, pro-chimera activists might have to promote the dignity of human-animal chimeric beings just as pro-lifers do now for the unborn. This would not be elevating animals to the level of people, but ensuring that the humanity in the chimera did not have its dignity violated (any more than it already has, by having been created as a chimera in the first place). [Back]
4 Slater, "Humouse"; and Dowie, "Gods and Monsters." [Back]
5 Newman "has grave concerns about genetically manipulating human embryos," because he believes it could lead to designer babies (which he dubs "yuppie eugenics") and the creation of human clones. Interestingly he claims, "I'm pro-choice.... I don't want to valorize the embryo in any way. But I think it's damaging to the human community to get into a mindset where you can produce human embryos for any purpose." Slater, "Humouse." [Back]
6 For example, "when the agency objected to using human embryonic cells to help create a chimera, ... Newman's lawyers pointed out [that] it is legal to abort 100-percent-human embryos, and would make no sense to grant part-human embryos greater protection." Dowie, "Gods and Monsters." [Back]
7 Leon R. Kass, "The Wisdom of Repugnance," in Leon R. Kass and James Q. Wilson, The Ethics of Human Cloning (Washington, D.C.: The AEI Press, 1998): 17-19. [Back]
8 President's Council on Bioethics, Reproduction and Responsibility: The Regulation of New Biotechnologies, pre-publication version (Washington, D.C.: President's Council on Bioethics, March 2004): 223, 222. See http://www.bioethics.gov/reports/reproductionandresponsibility/. [Back]
9 Pontifical Academy for Life, Prospects for Xenotransplantation: Scientific Aspects and Ethical Considerations (September 26, 2001), n. 10. The Pontifical Academy for Life considers the "personal identity" of someone "the relation of an individual's unrepeatability and essential core to his being a person (ontological level) and feeling that he is a person (psychological level)." (Ibid., n. 10, original emphasis.) [Back]
10 PBS, "A History of Xenotransplantation Experiments," http://www.pbs.org/wgbh/pages/frontline/shows/organfarm/etc/cron.html, from Frontline, episode "Organ Farm," March 27, 2001. [Back]
11 Pontifical Academy for Life, Prospects, n. 11. [Back]
12 Ibid., note 61. An exception is given only for gonad transplants which are performed in order to "restore hormonal function," and only if the "integrity of the subject's personal identity has been ensured" and a "disassociation [of the procedure] with procreation has been established." There have been interspecies brain cell injections (albeit not full brain transplants) done in the U.S.; for example, the biotech company GenVec (formerly known as Diacrin) has injected fetal pig brain cells into the brain of a stroke patient. GenVec, Inc., "Fetal Pig Cells Implanted in Stroke Patient," news release, September 22, 1999, http://www.corporate-ir.net/ireye/ir_site.zhtml?ticker=GNVC&script=418&1ayout=-6&item_id=441689. [Back]
13 Richard M. Twyman, "Genetic Engineering: Animal Cell Technology," in Encyclopedia of Cell Technology, vol. 2, ed. Raymond E. Spier (New York: John Wiley and Sons, 2000), 804-805; in the production of chimeric mice, only some of the chimeras integrate transgenic cells into the germ line. Also, M.H. Pineda, "Reproductive Patterns of Sheep and Goats," in McDonald's Veterinary Endocrinology and Reproduction, 5th ea., ed. M.H. Pineda (Ames, IA: Iowa State Press, 2003), 446: Creation of chimera "geeps" (goat-sheep) is only successful when the trophoblast (outer layer of the blastocyst, which contributes to the formation of the placenta) has been formed from the cells of the same species as the species into which the embryo is transferred to grow (meaning that not all the chimeras end up having their outer cell layer formed by the correct cell species). Also Graca Almeida-Porada and Esmail D. Zanjani, "A Large Animal Noninjury Model for Study of Human Stem Cell Plasticity," Blood Cells,Molecules, and Diseases 32.1 January-February 2004): 80: injection of human bone marrow cells into fetal sheep brings evidence of incorporation of the human cell lines into all three germinal cell layers of the sheep (endoderm, ectoderm, and mesoderm). [Back]
14 Almeida-Porada and Zanjani, "A Large Animal," 80; and Sylvia Pagan Westphal, "'Humanised' Organs Can be Grown in Animals," NewScientist.com (December 17, 2003), http://www.newscientist.com/news/news.jsp?id=ns99994492. [Back]
15 Judith A. Airey, "Human Mesenchymal Stem Cells Form Purkinje Fibers in Fetal Sheep Heart," Circulation, 109.11 (March 23, 2004): 1401-1407. [Back]
16 Gaia Vince, "Pig-Human Chimeras Contain Cell Surprise," NewScientist.com (January 13, 2004), http://www.newscientist.com/news/news.jsp?id=ns99994558; Brenda M. Ogle, et al., "Spontaneous Fusion of Cells between Species Yields Transdifferentiation and Retroviral Transfer in Vivo," FASEB Journal (published online January 8, 2004). The pig-human hybrids exhibited both human and pig surface markers and contained chromosomal DNA coding for both human and pig genes. [Back]
17 Steven Reinberg, "Scientists Create Mice with Human Immune Systems," HealthDay (April 1, 2004), http://www.healthday.com/printer.cfm?id=518212; Elisabetta Traggiai, et al., "Development of a Human Adaptive Immune System in Cord Blood Cell-Transplanted Mice," Science 304.5667 (April 2, 2004): 104-107. [Back]
18 Advanced Cell Technology, "Advanced Cell Technology Announces Use of Nuclear Transfer Technology for Successful Generation of Human Embryonic Stem Cells,"press release, November 12, 1998 [http://www.advancedcell.com/1998-11-12.htm] [Back]
19 Ying Chen et al., "Embryonic Stem Cells Generated by Nuclear Transfer of Human Somatic Nuclei into Rabbit Oocytes," Cell Research 13.4 (2003): 251-263. [Back]
20 Andy Coghlan, "First Human Clone Embryo Ready for Implantation," NewScientist.com (September 15,2003), http://www.newscientist.com/news/news.jsp?id=ns99994168. Granulosa cells are cells in ovaries that surround the oocytes. [Back]
21 The other meaning of the term refers to Adam's lack of female companionship. [Back]
22 John Paul II, Theology of the Body: Human Love in the Divine Plan (Boston: Pauline Books and Media, 1997): October 10, 1979. [Back]
23 Ibid., October 24, 1979: "We apply [the term 'original solitude'] to man in his totality. His body, through which he participates in the visible created world, makes him at the same time conscious of being 'alone.'" [Back]
24 Gn 1 :26-27: "God said: 'Let Us make man in our image, after our likeness.' ... God created man in his image, in the divine image He created him; male and female He created them." John Paul II points out that "the biblical narrative does not speak of his likeness to the rest of creatures, but only to God." John Paul II, Theology of the Body, September 12,1979. [Back]
25 John Paul II, Theology of the Body, September 12, 1979, note 1. [Back]
26 See Ex 22:18: "Anyone who lies with an animal shall be put to death"; and Lv 18:23: "You shall not have carnal relations with an animal, defiling yourself with it; nor shall a woman set herself in front of an animal to mate with it; such things are abhorrent"; also see Dt 27:21 and Lv 20:15-16. [Back]
27 See Dt 27:22, Lv 18: 6-14, Lv 20:17, 19-21. [Back]