On January 19, Dr. Mark Hughes, M.D., Ph.D., delivered a thought provoking lecture to a rapt, overflow crowd in The January Series 2001 on “The Human Embryo: Diagnosing Disease, Cloning, Stem Cell Research; We Can but Should We?” With slide-illustrated case studies, he made a compelling case for preimplantation genetic diagnosis (PGD) to enable parents at-risk for having a child with a severe genetic condition to minimize that risk. He concluded his presentation with the story of Lisa, a young girl dying of severe combined immunodeficiency (SCIDS) whose parents sought to have another child not only without SCIDS, but also one who could be a suitable donor of stem cells to potentially save Lisa’s life. Initially, Dr. Hughes was reticent to assist, fearing he was crossing an ethical boundary. But the father’s heartfelt plea convinced him of its legitimacy.

Last year, a similar story made national news. Lisa and Jack Nash of Englewood, Colorado, had a 6-year-old daughter, Molly, seriously ill with Fanconi anemia. They sought to have another child, one without the lethal genetic disease who would be a compatible stem cell donor to save Molly’s life.

Through PGD performed by the Reproductive Genetics Clinic in Chicago, Adam was born—free from Fanconi anemia and a perfect donor match for Molly. At the University of Minnesota, blood from his umbilical cord was used as a stem cell transplant to save Molly’s life.

Both SCIDS and Fanconi anemia are genetic conditions due to single gene mutations inherited as recessive conditions. Parents who are carriers of a recessive condition have a one-in-four probability of a child inheriting the condition (a three-in-four probability a child will not have the condition). The cell surface antigens (HLA) which need to be matched in transplants are very complex, but essentially inherited as a single set of linked genes.

The probability of any two siblings having the same HLA identity is one-in-four. The likelihood of avoiding the genetic condition in either of these conditions and matching HLA identities is three-in-sixteen (see figure for details). In the Nash’s case, only one of twelve embryos created met their criteria; providentially, that embryo successfully implanted and Lisa gave birth to Adam.

In PGD, a couple at-risk for a genetic condition they are striving to avoid in their children undergo in vitro fertilization following superovulation to produce numerous eggs. Approximately 2-3 days after onset of fertilization, when the embryos are at the 8-cell stage, one cell is plucked from each embryo and its DNA is tested to identify each embryo’s genotype.

Preimplantation genetic diagnosis raises several significant ethical questions. First, what is the moral status of unimplanted embryos? If their status is like human hair, fingernails, blood, or diseased tissues and organs, we have few qualms about creating, using, and discarding them.

If their status is like adult persons, we will have serious concerns about creating them, and prohibitions against using them for others’ purposes and discarding them. If their status is somewhere between those extremes, what is the appropriate awe, respect and reverence due individuals in the earliest stages of human development?

Second, what constitutes a severe genetic condition, one sufficiently severe perhaps to warrant PGD? Should it manifest itself in a significant reduction in life expectancy, greatly diminished quality of life or both? Persons with SCIDS usually suffer to die in infancy or childhood unless they are successful recipients of a stem cell transplant.

Persons with Fanconi anemia suffer many symptoms until they die no later than adolescence. Among genetic conditions such as cystic fibrosis, sickle cell anemia, Tay-Sachs disease, Hungtington disease, polycystic kidney disease, Down syndrome, predispositions to cancer, and colorblindness, which ones are sufficiently severe to consider PGD as an option?

Third, are we entering the realm of commodification? Are we beginning to view children as commodities, subject to quality control, perhaps to be rejected if they do not pass our criteria? Technology which permits us to diagnose and select against severe genetic diseases can also be used to select against any genetic identity, regardless of its severity.

The same technology makes it feasible for us to redesign our children, not just to correct severe genetic conditions, but to augment traits parents might find desirable. Are not children gifts of God, to be accepted, embraced, and nurtured through all their (and our) imperfections?

Fourth, what are we to do with the unimplanted embryos? There are five options: 1) cryopreserve them until the parents can transfer them to have additional children, 2) donate them in an adoption-like arrangement to an infertile couple desiring to have children, 3) cryopreserve them indefinitely, 4) use them in research, or 5) discard them. All couples undergoing in vitro fertilization should consider these issues before undergoing any procedure which might result in excess unimplanted embryos.

Fifth, does selecting against embryos with certain genetic conditions devalue persons who have those genetic conditions? Imagine your parents went to great lengths not to have another child like you. How might we use PGD without devaluing others?

Although I have voiced some significant ethical concerns with PGD, I believe it is morally permissible to use PGD under appropriate circumstances. As a Christian with a high regard for human life in all its stages, my hope is that couples considering PGD will not be mislead by its shear utility, but will carefully bear in mind these moral concerns and thoroughly seek all reasonable avenues and alternatives to minimize their occurrence.