Nature versus nurture Most of us have the intuition that, although our genes provide advantages and constraints, we retain great control over our lives. However, we develop a second, competing intuition that, like it or not, our genes determine our abilities, preferences, and emotions. We would like to think that we are much more than the sum of our genes, but scientists have apparently demonstrated that our genes determine some of our most complex behavioral and cognitive characteristics. The emphasis on genes as the primary mode of biological explanation has been particularly clear. in the commercialization of the Human Genome Project. In support of this project, Robert L. Sinsheimer, biologist and former chancellor of the University of California, Santa Cruz, asserted: “[i]n the deepest sense, we are who we are because of our genes.” . (Berkowitz 1996) Does the available scientific evidence really tell us that our genes determine our behavioral, emotional, and cognitive characteristics? Do single genes specify particular behavioral traits? To answer these questions, most nonscientists rely on superficial reports of new research findings that appear regularly in the lay press. These reports are oversimplified and can be shaped by the desire of journalists and scientists to create a compelling story. As a result, our perception of scientific evidence can be distorted by some dramatic findings, some of which may be false. Nowhere has this been clearer than in depicting the role of genes in determining uniquely human characteristics, involving our thoughts. , emotions and behaviors. Over the past decade, there have been highly visible reports locating genes for manic depression (Baron et al. 19...... middle of article......Sussex, KK Kidd , CR Allen, AM Hostetter and DE Housma 1987. Bipolar affective disorder linked to DNA markers on chromosome 11. Nature 325: 783-787 Gelernter, J., S. O'Malley, N. Risch, HR Kranzler, Krystal J, Merikangas K, Kennedy JL, and Kidd KK 1991. No association between an allele at the dopamine D2 receptor gene (DRD2) and alcoholism. . Hu, VL Magnuson, N. Hu and AML Pattatucci 1993. Link between DNA markers on X chromosomes and male sexual orientation 261: 321-327Kelsoe, JR, EI Ginns, JA Egeland, DS Gerhard, AM Goldstein , SJ Bale, DL Pauls, RT Long, KKKidd, G. Conte, DE Housman and SM Paul 1989. Reassessment of the linkage relationship between chromosome 11p loci and the gene for bipolar affective disorder in the ancient order of the Amish nature. 342: 238-243.