Molecular biologist Dean Hamer has blue eyes, light brown hair and the goofy sense of humor of a stand-up comic. He smokes cigarettes, spends long hours in a cluttered laboratory at the National Institutes of Health, and in his free time clambers up cliffs and points his skis down steep, avalanche-prone slopes. He also happens to be openly, matter-of-factly gay. What is it that makes Hamer who he is? What, for that matter, accounts for the quirks and foibles, talents and traits that make up anyone’s personality? Hamer is not content merely to ask such questions; he is trying to answer them as well. A pioneer in the field of molecular psychology, Hamer is exploring the role genes play in governing the very core of our individuality. To a remarkable extent, his work on what might be called the gay, thrill-seeking and quit-smoking genes reflects his own genetic predispositions. That work, which has appeared mostly in scientific journals, has been gathered into an accessible and quite readable form in Hamer’s provocative new book, Living with Our Genes . “You have about as much choice in some aspects of your personality,” Hamer and co-author Peter Copeland write in the introductory chapter, “as you do in the shape of your nose or the size of your feet.” Until recently, research into behavioral genetics was dominated by psychiatrists and psychologists, who based their most compelling conclusions about the importance of genes on studies of identical twins. For example, psychologist Michael Bailey of Northwestern University famously demonstrated that if one identical twin is gay, there is about a 50% likelihood that the other will be too. Seven years ago, Hamer picked up where the twin studies left off, homing in on specific strips of DNA that appear to influence everything from mood to sexual orientation. Hamer switched to behavioral genetics from basic research; after receiving his Ph.D. from Harvard, he spent more than a decade studying the biochemistry of metallothionein, a protein that cells use to metabolize heavy metals like copper and zinc. As he was about to turn 40, however, Hamer suddenly realized he had learned as much about metallothionein as he cared to. “Frankly, I was bored,” he remembers, “and ready for something new.” Instrumental in Hamer’s decision to switch fields was Charles Darwin’s The Descent of Man, and Selection in Relation to Sex. “I was fascinated to learn that Darwin seemed so convinced that behavior was partially inherited,” he remembers, “even though when he was writing, genes had not been discovered, let alone DNA.” Homosexual behavior, in particular, seemed ripe for exploration because few scientists had dared tackle such an emotionally and politically charged subject. “I’m gay,” Hamer says with a shrug, “but that was not a major motivation. It was more of a question of intellectual curiosity–and the fact that no one else was doing this sort of research.”
