"Carlson reveals the various scientific advances, in both methods and understanding, that allowed researchers to identify anatomical structures, gametes, sex hormones, sex chromosomes, and ultimately, a firm comprehension of the genetics of sex. . . . This scientific story of discovery is quite fascinating."—Barbara Baumgartner, Washington University, St. Louis"Carlson does an excellent job presenting the researchers who, over time, worked out the details of sex determination and differentiation. Highly informative and instructive."—Johan Verhulst, MD, Kinsey Institute