Simon LeVay served on the faculty of Harvard Medical School for 13 years and on the faculty of the Salk Institute for Biological Studies for 8 years. Most of his research concerned the function and development of the mammalian visual system, but he also conducted research into the biological basis of human sexual orientation.
In 1991 he published a study in Science that drew international attention. This study reported on a structural difference between the brains of heterosexual and homosexual men—specifically, a large difference in the volume of a region of the hypothalamus that is known to be involved in the regulation of male-typical sexual behavior. This report helped trigger a wave of new research; most of the findings have supported an important role for biological factors such as genes and prenatal hormones in the development of sexual orientation. Because people’s beliefs about the origin of homosexuality influence their attitudes towards gay people, this body of research has likely made some contribution to the increasing acceptance of gay people in the United States and elsewhere over the last 25 years.
Although he left laboratory research in 1993, he has remained active in the scientific community through his writing and by participation in scientific meetings and online interest groups. He has given innumerable public lectures on the topic of sexual orientation, been interviewed on national and local TV and radio programs, and is regularly sought out for his interpretation of new research findings. He has testified in legal cases concerned with gay rights and consulted with church groups that are debating such topics as the ordination of lesbian and gay ministers to the extent he is now considered an éminence grise in the field of sexual orientation research.
He has published several books in the field of human sexuality, including a college textbook, Discovering Human Sexuality. His non-academic books on sex-related subjects are The Sexual Brain (MIT Press, 1993), City of Friends (MIT Press, 1997), Queer Science (MIT Press, 1997), and Gay, Straight, and the Reason Why (2nd edition, Oxford University Press, 2016).
Other books include The Earth in Turmoil: Earthquakes, Volcanoes, and Their Impact on Humankind (with Kerry Sieh, W.H. Freeman, 1998), Here Be Dragons: The Scientific Quest for Extraterrestrial Life (with David Koerner, Oxford University Press, 2001), Healing the Brain (with Curt Freed, Times Books, 2002), and When Science Goes Wrong (Plume, 2008) which made the New York Times paperback bestseller list. He has also published two novels: Albrick’s Gold (Richard Kasak Books, 1997), and The Donation of Constantine (2013).