The Boston XYY Case

Abstract

O n June 20, newspapers reported that Dr. Stanley Walzer, a Harvard psychiatrist, had curtailed a controversial chromosome screening study which detected male children with the XYY chromosome pattern. Dr. Walzer's decision was the outcome of a year-and-ahalf of charges and counter-charges which swirled around the study, its methods, its legitimacy, its scientific value, and ultimately around the tactics used to oppose the study. In the latter half of 1974 the question of whether the study should continue was taken up first by the Harvard Medical School standing committee on medical research, then by the human studies committee, and finally by the full medical school faculty. Though all these bodies ruled in the study's favor, critics remained unsatisfied. Indeed, earlier opponents (a Science for the People group, informally led by Dr. Jonathan Beckwith at Harvard and Dr. Jonathan King of MIT) were joined by the Washington-based Children's Defense Fund. Dr. Walzer attributes his decision to cease the screening portion of his study to the emotionally exhausting atmosphere created by the controversy.' For the moment, then, the debate in Boston may be settled; the issues which fueled it are not. Our society has entered a period in which it is technically possible to characterize the genotypes of large numbers of individuals by relatively simple biochemical or chromosomal screening tests. The potential benefits and risks of these tests vary enormously. The early detection of PKU (phenylketonuria) can prevent an incipient genetic disease, and hence has clear health benefits. In other cases-like the XYY genotype-the benefits of screening tests are more problematic. In the midand late sixties, studies of the chromosome composition of inmates in mental-penal institutions revealed that roughly two percent had the XYY chromosome type. At the same time the incidence of XYY in studies of consecutive newborns was determined to be about 0.11 percent.2 This higher-thanexpected rate of XYY individuals in prisons and mental hospitals led to association of the chromosome with "aggressive or sexual psychopathology." This premature characterization of the genotype, coupled with wide-spread publicity, has raised the definite possibility of stigmatization for individuals found to have the XYY genotype. These initial blunders have seriously jeopardized the possibility of further study. Statistically speaking, the vast majority of XYYs are not likely to end up in institutions. Assuming (for purposes of calculation) that one in 500 adult white males are in mental-penal institutions, in every group of one million males there would be 1100 XYYs, about forty of whom would be in mental-penal institutions at some point in their lives.3 From this illustrative calculation, it may also be inferred that approximately 1070 out of 1100 XYYs, or more than ninety-seven percent, will probably not end up in mental-penal institutions; for many of them the prospects are simply to lead normal, socially productive lives. As Ernest Hook points out, "Discovery of an extra sex chromosome in a male hardly predicts antisocial behavior with the confidence, for instance, that the observation of trisomy 21 (the chromosome pattern associated with mongolism) predicts mental retardation."4 Similarly, after an extensive review of the literature on the XYY genotype, Digamber Borgaonkar and Saleem Shah conclude: "In view of the phenotypic heterogeneity which clearly seems to accompany the XYY chromosomal constitution, it would be incorrect to suppose a narrow range of phenotypic variation or that a typical syndrome exists."5