The Perils of Treading on Heredity

By Philip Elmer-DeWitt

The prospect is intoxicating. By mapping and manipulating tiny genes, man . could conceivably conquer diseases, improve upon his natural abilities and perhaps even control his own destiny. But just because miracles might someday be possible does not necessarily mean that they should all be performed. The tools of molecular biology have enormous potential for both good and evil. Lurking behind every genetic dream come true is a possible Brave New World nightmare. After all, it is the DNA of human beings that might be tampered with, not some string bean or laboratory mouse. To unlock the secrets hidden in the chromosomes of human cells is to open up a host of thorny legal, ethical, philosophical and religious issues, from invasion of privacy and discrimination to the question of who should play God with man's genes.

The opportunities and dilemmas created by the new genetic knowledge begin even before birth. It is already possible, through a variety of prenatal tests, to determine whether a child will be a boy or a girl, retarded or crippled, or the victim of some fatal genetic disorder. The question of what to do with that information runs squarely into the highly charged issue of abortion. Many could sympathize with a woman who chooses to terminate a pregnancy rather than have a baby doomed to a painful struggle with, say, Tay- Sachs disease or Duchenne muscular dystrophy. But what about the mother of three daughters who wants to hold out for a son? Or the couple that one day may be able to learn whether an unborn baby has a minor genetic blemish? Only the most hardened pro-choice advocate would argue that prospective parents have the right to abort fetus after fetus until they get the "perfect" baby.

Complicating such decisions is the fact that genetic prognostication will probably never be an exact science. Technicians may someday be able to determine that a fetus has a predisposition to heart disease, certain cancers, or a variety of psychiatric illnesses. But they will not be able to predict precisely when -- or even if -- the affliction will strike, how severe it will be and how long and good a life the baby can expect. As scientists learn to detect ever more minute imperfections in a strand of DNA, it will become increasingly difficult to distinguish between genetic abnormalities and normal human variability. "We haven't thought much about how to draw the line," admits Arthur Caplan, director of the Center for Biomedical Ethics at the University of Minnesota. "It is going to be one of the key ethical challenges of the 1990s."

History shows that genetic misinformation can be severely damaging. Take, for example, the supposed link between the XYY chromosome pattern and criminal behavior. In 1965 a study of violent criminals in a Scottish high-security mental institution found that a surprisingly high percentage had a particular chromosomal abnormality: in addition to the X and Y chromosomes normally found in men, each carried an extra Y, or "male" chromosome. The press and public seized on the idea that these so-called supermales were genetically predestined to a life of crime. That interpretation proved false. Further investigations showed that the vast majority of men with the XYY pattern -- an estimated 96% -- lead relatively normal lives. But before the matter was put to rest, a variety of measures were proposed to protect society from the perceived threat. One group of scientists urged massive prenatal screenings, presumably to allow parents to arrange for abortions. Others initiated long- range studies to identify XYY infants and track their progress over the years through home visits, psychological tests and teacher questionnaires. These dubious efforts were eventually abandoned, but not before a group of innocent youngsters had been unfairly labeled as somehow inferior.

Adults could be wrongly branded as well. Life- and medical-insurance companies might one day require that potential customers have their genes screened, presumably so that people likely to develop fatal or disabling diseases could be charged higher premiums, or possibly turned away. Insurers have already used a similar policy to avoid covering individuals at high risk for AIDS, a practice now banned in several states. Unless it is prohibited by law, employers could conceivably try to guarantee a healthy work force by asking job applicants to submit to genetic screening. Clearly, there is a potential for widespread discrimination against those whose genes do not meet accepted standards.

Once someone's genes have been screened, the results could find their way into computer banks. Without legal restrictions, these personal revelations might eventually be shared among companies and government agencies. Just like a credit rating or an arrest record, a DNA analysis could become part of a person's permanent electronic dossier. If that happens, one of the last vestiges of individual privacy would disappear.

Even if genetic information is kept private, the knowledge gained can be profoundly troubling to the individuals involved. It is one thing to uncover a genetic enzyme deficiency that can be effectively treated through diet. But what about people who fear they have inherited a debilitating disease for which there is yet no treatment or cure? Some might want advance knowledge so they can prepare their families and put what is left of their lives in order. Others might prefer not knowing anything at all. "We may be able to see into the future," says Doreen Markel, a genetic counselor at the University of Michigan's Neurology Clinic. "But ask yourself: Do you really want to know what you're going to die of?"

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."

The possibilities for gene therapy will be limited for the near future. If gene transplants are performed on tissue cells -- bone-marrow cells, for instance -- the altered genes will die with the patient; they cannot be passed on to any children the patient might subsequently have. Someday, however, it may be possible to change genes in germ cells, which give rise to sperm or eggs. If that feat is accomplished, the new genes would be transmitted to one generation after another.

That is what most frightens the foes of genetic engineering. If biologists can change the course of heredity, they can try to play God and influence human destiny. In 1983 activist Jeremy Rifkin, a longtime opponent of many kinds of genetic research, and several dozen theologians mounted an unsuccessful effort to persuade Congress to ban all experiments on human germ cells. Said Avery Post, president of the United Church of Christ, at the time: "We're not good enough or responsible enough. There is no question about it. We will abuse this power."

No geneticist is currently planning to transfer genes to human germ cells. Even though mankind has been playing God since biblical times, rearranging the germ lines of crops and farm animals to suit human needs, researchers do not advocate extending such genetic tinkering to people. But medical scientists have an obligation to protect humanity against disease and pestilence. Once it becomes possible to eradicate a gene that causes a fatal disorder, and thus keep it from passing to future generations, it will be criminal not to do so. As director of the Human Genome Project, James Watson contends that the research has a crucial humanitarian mission. Says he: "The object should not be to get genetic information per se, but to improve life through genetic information."

Fortunately, the most ardent supporters of genetic research are the first to admit the potential for abuse and see the need for ground rules. Many ethicists and scientists who have studied the issues agree on certain basic principles:

-- Individuals should not be required to submit to genetic testing against their will.

-- Information about people's genetic constitution should be used only to inform and never to harm.

-- The results of a genetic assay should be held in strict confidence.

-- Genetic engineering in humans should be used to treat diseases, not to foster genetic uniformity.

Knowledge is power, the saying goes. It can be dangerous, but it can just as easily be used wisely. "I do have faith," says Case Western's Murray. "Not that the judgment of people is always right, but that eventually we will preserve a good measure of fairness and justice. If we can absorb Copernicus and Galileo, if we can absorb Darwin and Freud, we can certainly absorb mapping the human genome."

One thing is certain: the genie cannot be put back into the bottle. Like atomic energy, genetic engineering is an irresistible force that will not be wished or legislated away. The task ahead is to channel that force into directions that save lives but preserve humanity's rich genetic heritage.

With reporting by Andrea Dorfman/New York and J. Madeleine Nash/San Francisco