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

Simon LeVay 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 New York Times best-seller, When Science Goes Wrong.

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.

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.

Publishers Weekly

The nature vs. nurture wars over the development of homosexuality have been pretty definitively decided in favor of nature. In this survey of what makes people gay, lesbian, bi, or straight, neuroscientist LeVay (When Science Goes Wrong) brings readers up-to-date on the current state of knowledge. Other recent books have covered much of the same territory, but LeVay's is the most comprehensive. He begins by tackling the seemingly simple question "What is sexual orientation?" As the book progresses, he discusses how gayness is not monolithic; rather, there seems to be different kinds of homosexuality. Some people claim to be able to identify gays using "gaydar," but LeVay says differences between straights and gays go beyond body language to include visuospatial abilities (e.g., lesbians, like straight men, have better spatial abilities than straight women) and verbal fluency. He reviews current thinking on the role of genes and how testosterone levels may influence the fetus's development. LeVay comes close at times to dry recitation of research results, but 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. 20 b&w line drawings. (Oct.)

Introduction

One What Is Sexual Orientation? 1

Two Why We Need Biology 27

Three The Outline of a Theory 45

Four Childhood 73

Five Characteristics of Gay and Straight Adults 97

Six The Role of Sex Hormones 129

Seven The Role of Genes 157

Eight The Brain 191

Nine The Body 221

Ten The Older-Brother Effect 247

Eleven Conclusions 271

Glossary 297

Notes 309

Bibliography 331

Author Index 393

Subject Index 397