Whether we like it or not, genetic testing will almost certainly become routine medical practice within the next 25 years. Integrated circuit chips already exist that can perform 400 genetic tests simultaneously, thus greatly reducing the costs. At least one company is already working on a prototype for a handheld genetic tester that would allow primary care physicians to perform hundreds or thousands of genetic tests on a simple blood smear in just a few minutes. "Genetic report cards" for children are not very far off at all. The use of such widespread testing poses a variety of ethical dilemmas. One problem that has not been appreciated sufficiently, however, is the question of how to interpret the test results. Because of the ways the genes implicated in diseases are discovered and marketed, quantitative analysis of the tests can be extremely misleading. The difficulty is that we simply do not have sufficient information about variance in genetic and other factors in the general population to make accurate projections of a patient's risk, given the presence of a gene. This uncertainty is obscured, however, when we provide the patient with a numerical analysis of risk because it is well established that people tend to overestimate the information content of numerical projections. This situation is made far worse by the fact that we do not have enough adequately trained genetic counselors to handle the load that will soon be placed on them land studies have shown that physicians are generally very poorly prepared to act as accurate sources of information on complex genetic issues). For these reasons, I argue that access to genetic testing should be treated the same way as access to new medical procedures and medications - namely, withheld from the general public until proven safe and effective in large-scale trials. This is certain to be an unpopular policy, but it seems the only way to prevent a great deal of abuse of genetic tests.
