Richard Green was one of the earliest LGBTQ allies in the mental health profession.

Richard Green, a longtime LGBTQ ally who was one of the first psychiatrists to speak out against the labeling of homosexuality as a mental disorder, has died at age 82.

Green died of esophageal cancer April 6 at his home in London, his son, Adam Hines-Green, told The New York Times.

In 1972, early in his career, Green wrote an article in The International Journal of Psychiatry taking issue with “the premise that homosexuality is a disease or a homosexual is inferior.” The following year, the American Psychiatric Association dropped homosexuality from its list of mental disorders.

“Those were times when, if you spoke up in support of homosexuals, people immediately thought that you were secretly homosexual yourself, or had unresolved sexual issues,” Jack Drescher, a clinical professor of psychiatry at Columbia University, told the Times. “Richard was very much heterosexual, and it took a lot of courage to argue for gay people.”

Even earlier, in 1962, Green testified on behalf of a Nicaraguan man who was facing deportation from the U.S. for being gay. The man won the right to remain in the U.S. Later, Green “testified on behalf of a transgender woman who was suing to keep her job as a pilot, and a transgender parent who was suing for child visitation,” the Times reports.

Green eventually completed a law degree, and he put that to use in support of LGBTQ rights as well. In 1990 he volunteered his legal services in a case brought by the American Civil Liberties Union against the Boy Scouts of America’s ban on gay scoutmasters. Although the BSA won the suit, it finally dropped the prohibition in 2015.

Green was also the author of The “Sissy Boy Syndrome” and the Development of Homosexuality, a book that reviewed his findings that “many effeminate boys grow up to be gay,” the Times notes. A New York native, he taught at universities in the U.S. and the U.K. and founded International Academy of Sex Research.

Survivors, besides his son, include his companion, Claire Loveday.