Gay, Straight, and the Reason Why: The Science of Sexual Orientation

Although the book's chief appeal probably will be to professionals dealing with these issues, other interested readers will find it an informative and generally approachable read." (Publishers Weekly)

Simon LeVay, a former Harvard neuroscientist, has written, Gay, Straight, and the Reason Why: The Science of Sexual Orientation, a comprehensive, engaging and occasionally quite funny look at the current state of the research on the topic." (Schuyler Velasco, Salon)

This book will serve both as a resource for researchers looking for what is yet unknown and what questions need further research and as a fascinating read for the educated layperson, who will be intrigued by some of the factors that may relate to homosexuality... Recommended. (Choice)

LeVay also does a nice job illustrating that the argument for sexual orientation as determined is not a singular cause-and-effect argument...Yet, it is important for scholars and clinicians alike across various paradigms to be aware of the research reviewed in Gay, Straight, and the Reason Why. (PsycCritiques)

Simon LeVay's book, Gay, Straight, and the Reason Why, offers an excellent review of scientific research on the causes and correlates of sexual orientation. It provides a clear and comprehensive summary of recent studies of sexual orientation- a review that should be useful to lay people and journalists as well as to professionals in the field. LeVay has a knack for describing complicated scientific topics- brain anatomy, behavior genetics, endocrinology, cognitive psychology- in straight-forward and easy-to-understand ways. He provides the reader with a good sense of where research on sexual orientation stands today, and where further research is needed. (Richard Lippa, Sex Roles)

The theory that sexual orientation has a biological basis receives support in neuroscientist Simon LeVay's book. Relating evidence from genetics, neuroscience and developmental biology, he suggests that prenatal interactions between hormones and the developing brain influence adult sexuality. (Nature)

What causes a child to grow up gay or straight? In this book, neuroscientist Simon LeVay summarizes a wealth of scientific evidence that points to one inescapable conclusion: Sexual orientation results primarily from an interaction between genes, sex hormones, and the cells of the developing body and brain.

LeVay helped create this field in 1991 with a much-publicized study in Science, where he reported on a difference in the brain structure between gay and straight men. Since then, an entire scientific discipline has sprung up around the quest for a biological explanation of sexual orientation. In this book, LeVay provides a clear explanation of where the science stands today, taking the reader on a whirlwind tour of laboratories that specialize in genetics, endocrinology, neuroscience, cognitive psychology, evolutionary psychology, and family demographics. He describes, for instance, how researchers have manipulated the sex hormone levels of animals during development, causing them to mate preferentially with animals of their own gender. LeVay also reports on the prevalence of homosexual behavior among wild animals, ranging from Graylag geese to the Bonobo chimpanzee.

In this revised edition LeVay broadens his horizons. He adds a new chapter on bisexuality, reviews some uncommon forms of sexuality such as asexuality and pedophilia, and considers whether there could be a biological basis for subtypes of gay people such as "butch" and "femme" lesbians.

Although many details remain unresolved, the general conclusion is quite clear: A person's sexual orientation arises in large part from biological processes that are already underway before birth.