Christian Brugger explores the complex world of bioethics in the 21st century . . .
Imagine you’re an official with the Vatican’s Congregation for the Doctrine of the Faith, and you receive a memo from the Holy Father asking for your ethical opinion on three innovations in the field of bioethics.
The first concerns a variation of in vitro fertilization (IVF) to help patients potentially to overcome the debilitating effects of mitochondrial DNA (m-DNA) disease. But in order to gain these benefits, IVF embryos need to be created using the biological material from three parents. The second technique uses stem cells from human fingernails and toenails to help amputees grow new limbs, and the third involves growing human organs inside a pig.
Your initial response is a combination of fascination and repugnance. But you don’t want to jump to any conclusions because of the “yuck factor.” Nor do you want to naively approve morally objectionable techniques. Realizing that not all bioethical techniques are created equal, you critique each using principles of Catholic morality.
“Three parent” embryos. Because it uses a form of IVF, you already know it’s ethically objectionable. IVF transmutes the begetting of new human life from the context of self-giving in marital intercourse to the making of an object by a laboratory technique.
But you suspect the grounds for objection stretch even wider. The technique can be performed in two ways. In the first, a woman who suffers from m-DNA disease has one of her oocytes (eggs) engineered to remove all infected m-DNA. That m-DNA exists only in her egg’s cytoplasm, not in its nucleus. Another egg, from a donor, with an uninfected cytoplasm is needed. Two eggs: one with “good” cytoplasm, one with a “good” nucleus are combined, and the resulting egg is fertilized with male sperm. A human being comes into existence who allegedly doesn’t suffer from m-DNA disease.
There are several problems with this. First, we don’t know if this would cure the disease. Moreover, transferring an egg nucleus is complicated and would take many trials to perfect. Further, we could not possibly be sure of the long-term effects on human development. Thus it would subject embryos — human beings — to the risk of grave developmental harm. Finally, the genetic composition of the embryo derives from “three parents.” This fact is part of the embryo’s identity and so will be an important part of the future adult’s self-understanding. Parentage confusion from this technique has been greatly minimized by some bioethicists, but shouldn’t be dismissed.
Since human dignity is violated in this situation, you decide to advise the Holy Father to oppose the technique and to back forms of research that do not destroy human beings or subject them to unreasonable risk of physical and psychological harm.
Nail stem cells. The cells used in the second type of research are adult stem cells harvested from human fingernails and toenails. You know that adult stem cell research is — in principle — morally unproblematic, so you examine the research with interest. You learn that in both mice and humans, the regeneration of an amputated digit involves the activity of stem cells found in the nails.
Studies have shown that if an amputation removes the nail stem cells, no regeneration of the corresponding digit occurs. If the nail stem cells remain, regrowth can occur. The technique’s principle requires learning how nail stem cells are biochemically signaled to regenerate limbs. If that can be understood more fully, then researchers might be able to artificially signal the cells from amputees to grow them new limbs. You decide to advise the Holy Father to cautiously support further research into the matter.
Pig incubators. The third technology involves injecting a human stem cell into a pig embryo that’s been genetically engineered not to develop a certain kind of internal organ (e.g., a pancreas). The embryo is then transferred into the uterus of a female pig to develop to birth; the developing pig develops with a human organ!
The technique at first sounds benign, sort of like using a pig’s body as a kind of incubator to grow human organs. But you learn that the human stem cell injected into the pig embryo does not merely develop into a human organ. Human cells incorporate randomly and in unknown proportions throughout the developing organism.
In other words, the technique produces a human-pig chimera, which may even generate human rather than porcine sperm and possess a significant percentage of human brain matter. Although organs might be prompted to grow, the problematic nature of creating human-non-human organisms leads you to recommend against supporting further research using this technique.
CHRISTIAN BRUGGER, PH.D., is the J. Francis Cardinal Stafford Chair of Moral Theology at St. John Vianney Theological Seminary in Denver, Colo.