Science: The Perils of Treading on Heredity

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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?"