The term "homosexual transsexual" was defined by Kurt Freund in 1974, and is used by various sexologists and psychiatrists to describe trans women who are attracted to men, though occasionally they use it to describe trans men who are attracted to women. The concept of a taxonomy based on transsexual sexuality was first proposed by physician Magnus Hirschfeld in 1922, and codified by endocrinologist Harry Benjamin in the Benjamin Scale in 1966, which was published in the influential book "The Transsexual Phenomenon". Benjamin wrote that researchers of his day thought that attraction to men while feeling that oneself is a woman was the factor that distinguished a transvestite from a transsexual. He wrote, "The transvestite - they say - is a man, feels himself to be one, is heterosexual, and merely wants to dress as a woman. The transsexual feels himself to be a woman ("trapped in a man’s body") and is attracted to men."