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

"This book is the best available summary of the science of sexual orientation. I was struck reading it how much has happened in the field since LeVay's last book, Queer Science. It will be useful both to a general reader---Simon is such a clear explainer---and to a specialist."---J. Michael Bailey, Northwestern University

"LeVay offers a lucid, authoritative account of the exploding literature on the biology of human sexual orientation. Gathering information from a dizzying variety of studies, encompassing genes, hormones, psychology, and the neurosciences, LeVay brings into sharp focus the overwhelming evidence that nature has a say in whom we love."--- S. Marc Breed Love, Michigan State University

"The question of how people become gay or straight is fraught with controversy, yet Simon LeVay has the remarkable ability to tackle this subject in a lively, engaging, and balanced way. He carefully reviews the literature about sexuality and sexual orientation and presents his views crisply, thoughtfully, and always with a touch of humor. There are no axes to grind or political agendas at work here: LeVay dispassionately offers a model of" sexual orientation that brings together key research findings. This hook is compelling, enjoyable reading and a must for anyone interested in the biological hases of sexual orientation,"--- Bradley Cooke, Neurosciencc Institute, Georgia State University

"Simon LeVay provides us with yet additional evidence of both his mastery of the research literature on sexual orientation and his skill at writing about science so that non-scientists can appreciate it. This book should be mandatory reading for everyone needing to understand the evidence for the biological basis of sexual orientation---legislators, members of the clergy, journalists, pundits, and parents."---Dennis Mcfadden, University of Texas at Austin

"Few scholars are as intellectually well-positioned as Simon LeVay to synthesize the proliferation of scientific research on sexual orientation that has blossomed since the publication of his pioneering brain study twenty years ago. This book is rigorous, insightful, and balanced. It provides a welcome antidote to the uninformed debate on this topic, which seems all too rife."---Paul L. Vasly, University of Lethbridge

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 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 homosexuality among wild animals, ranging from Graylag geese to the Bonobo chimpanzee.

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. LeVay also makes it clear that these lines of research have a lot of potential because, far from seeking to discover "what went wrong" in the lives of gay people, attempting to develop "cures" for homosexuality, or returning to traditional explanations that center on parent-child relationships, various forms of "training," or early sexual experiences, our modern scientists are increasingly seeing sexual variety as something to be valued, celebrated, and welcomed into society.

Simon Levay, Ph.D., is a British-born neuroscientist who has served on the faculties of Harvard Medical School and the Salk Institute for Biological Studies. He has written ten previous books, including the textbook Human Sexuality (Sinauer, 3rd edition 2009) and the New York Times best-seller, When Science Goes Wrong (Penguin, 2008).