Science: The Perils of Treading on Heredity

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The questions multiply as the science progresses. Thomas Murray, director of the Center for Biomedical Ethics at Case Western Reserve University, acknowledges that some people are worried that a complete map of the genome might somehow "diminish our moral dignity . . . reduce us somehow to nothing more than the chemical constituents of our bodies." But knowing the entire sequence of DNA base pairs is like having the full musical notation of Beethoven's Ninth Symphony, he says. "In no way does that knowledge diminish the grandeur of the symphony itself."

University of Washington ethicist Albert Jonsen is concerned that people with grave illnesses might be viewed simply as carriers of genetic traits. "Rather than saying 'Isn't that family unfortunate to have a schizophrenic son,' we'll say 'That's a schizophrenia family.' " Advocates for the handicapped fear that in the future the physically afflicted may no longer be seen as unfortunates worthy of special treatment, but as "wrongful births," genetic errors committed by parents who failed to take proper action against a defective gene.

To speak in terms of eliminating genetic defects is to tread on slippery scientific and ethical ground. As any biologist will testify, genetic variety is the spice of life, a necessary ingredient to the survival of a species. Genes that are detrimental under certain conditions may turn out to have hidden benefits. Sickle-cell anemia, for example, is a debilitating blood disease suffered by people of African descent who have two copies of an abnormal gene. A person who has only one copy of the gene, however, will not be stricken with anemia and will in fact have an unusual resistance to malaria. That is why the gene remains common in African populations.

Even to label genes as defective can be dangerous. In the 19th century new discoveries about heredity and evolution gave rise to the eugenics movement -- a misguided pseudo science whose followers thought that undesirable traits should be systematically purged from the human gene pool. Believers ranged from the American eugenicists of the early 1900s, who thought humans should be bred like racehorses, to the German geneticists who gave scientific advice to the leaders of the Third Reich, instructing them on how the species might be "purified" by selective breeding and by exterminating whole races at a time.

No geneticist today would even talk about creating a master race. Scientists are careful to point out that experiments in gene therapy will be aimed at curing hereditary disease and relieving human suffering, not at producing some sort of superman. But what if people want to use the technology to improve genes that are not defective but merely mediocre? Could genetic engineering become the cosmetic surgery of the next century? Will children who have not had their genes altered be discriminated against?

Scientists agree that it would be reprehensible to try to move too far in the direction of genetic uniformity. "The improvement and enhancement of genetics to some sort of optimum is not a function of medicine," observes the University of Minnesota's Caplan. "Very soon the medical fields are going to have to state clearly that their primary goal is the elimination and cure of disease and disability."