In the first section, Friedman and Downey stress the importance of "extrapsychoanalytic" research in the fields of genetics, psychoendocrinology, psychological development, and sexology. The authors believe that psychoanalysis has much to offer in its ability to explore one individual deeply, but theories of normative development require more statistically based sciences that rely not only on an exploration of meaning but also on specific physical observations. As examples, they rightly point out that psychoanalytic theories failed to uncover clitoral orgasm or the sex arousal cycle in women. Also, psychoanalysis started from a theoretical assumption of personality pathology in homosexual people that was not contradicted empirically until the 1960s by the work of Evelyn Hooker. Until recently, the authors point out, psychoanalysis approached homosexuality as only "a special instance of a general problem." Friedman and Downey accurately discuss the dangers of psychoanalytic theorizing divorced from basic science and insist on a systems approach to human sexuality that integrates clinical and theoretical understanding.