SIMON LEVAY, Ph.D. is a British-born neuroscientist turned science writer and teacher. He was educated at Cambridge University, UK and the University of Göttingen, Germany. In 1971, he moved to the United States. He has served on the faculty of Harvard Medical School and the Salk Institute for Biological Studies, and has taught at Harvard, the University of California, and Stanford University, all USA. LeVay has authored over 40 scientific studies; the best known of these is a 1991 report in Science that described a difference in brain structure between heterosexual and homosexual men. This study helped spark a wealth of new research on the biology of sexual orientation.

LeVay is the author or coauthor of nine books, some in the area of human sexuality and others on a broader range of scientific topics. JANICE BALDWIN, Ph.D. is a sociologist at the University of California, Santa Barbara, USA. She is co-author, with her husband John Baldwin, of numerous studies and articles in the area of sexuality and sex education, as well as the textbook Behavior Principles in Everyday Life , now in its fourth edition. The Baldwins co-teach an undergraduate Human Sexuality course that is regularly voted Best Course at UCSB. They also teach an advanced seminar course on the same topic. The Baldwins have been named as Best Professors on several occasions.