Rosalyn S. Yalow’s opinion essay (The Scientist, June 13, 1988, page 11) is interesting but avoids the real threat of radiation: mutation. She describes a variety of inconclusive studies about low levels of radiation and cancer but misses the main point. Radiation causes mutations. Cancer can result from mutations by an indirect, vaguely understood process. But mutations are a permanent part of the human population. As a matter of public policy, the question is how much of a mutational load are we as a population willing to tolerate. As private individuals who look forward to the future of human populations, we all should be apprehensive of the decisions of public policy makers.
F.M. BUTTERWORTH
Professor of Genetics
Oakland University...