Richard Isay bases the views he expresses in this book on his analytic and psychotherapeutic work with forty homosexual men over the past twenty years. In his introduction, as well as throughout the volume, he expresses the fundamental conviction that "like heterosexuality, homosexuality is constitutional in origin" (p. 4). Furthermore, he explicitly states: "While I regard sexual orientation itself as immutable from birth, the manner in which it is expressed appears to have multiple and diverse roots that may be profoundly influenced by a variety of early experiences" (p. 2).

It is a truism that sexuality has constitutional roots, i.e., that it is dependent on the genome that interacts with the environment and eventually leads to the phenotypical manifestations, including the choice of the sexual object. There is no evidence, however, that