Physician Harry Benjamin published The Transsexual Phenomenon in 1966, outlining ways transgender people could medically transition. Benjamin argued that a person's identity could not be changed and that a doctor's responsibility was to help transgender people live fuller and happier lives as the gender they identified with. Months after publication, the first "sex change" program in the United States was established at the John Hopkins University Medical School.

The book was notably financially backed by philanthropist and trans advocate Reed Erickson.