Arielle Emmett | Aug 19, 2001 | 5 min read
Unlike the chicken-and-egg dilemma, scientists know that genes come before the environment. In genetically based diseases, however, the question is not when but how. How do environmental conditions and lifestyle choices interact with a person's molecular structure? "We're all groping in the dark to find out how to get a handle on this complexity," says Marianne Berwick, an epidemiologist at Memorial Sloan-Kettering Cancer Center, New York. Although scientists can now assess exposure levels to