Dr Bailey is a psychologist, behavioural geneticist, and professor at Northwestern University. His research on the etiology of sexual orientation led him to the topic of transsexualism in natal males. In 2003, his book The Man Who Would be Queen, about 2 types of transsexualism (HSTS and AGP), launched the concept of Blanchard's Typology into the mainstream, and Bailey into hot water with trans activists.

The Man Who Would Be Queen is no longer in print, but is available as a free PDF: https://www.nap.edu/login.php?record_id=10530&page=https%3A%2F%2Fwww.nap.edu%2Fdownload%2F10530