Richard Green (born 6 June 1936) is an American sexologist, psychiatrist, lawyer, and author specializing in homosexuality and transsexualism, specifically gender identity disorder in children. He once sparked a debate in a special issue of the Archives of Sexual Behavior regarding whether pedophilia should be declassified as a mental illness by the American Psychiatric Association. Green does not condone pedophilia and instead believes that the APA should classify/treat it differently.
Green was born in Brooklyn, New York.  He earned his A.B. from Syracuse University in 1957, his M.D. from Johns Hopkins University School of Medicine in 1961, and his J.D. from Yale Law School in 1987.
Beginning in the early1960s, Green and John Money collaborated on publications about boys displaying substantial cross-gender behavior]. In 1969 they co-edited "Transsexualism and Sex Reassignment", published by Johns Hopkins Press. Green was founding editor of Archives of Sexual Behavior in 1971, serving as Editor for 30 years, and founding president of the International Academy of Sex Research in 1974. In 1979 Green was a founding committee member of the Harry Benjamin International Gender Dysphoria Association and served as president from 1997-1999. He previously directed the human sexuality program at the State University of New York at Stony Brook. He has been Professor of Psychiatry at the University of California, Los Angeles and Professor of Psychological Medicine, Imperial College, London. He was on the faculty of Law at UCLA and Cambridge.
During the APA's heated debate in the early 1970s about the declassification of homosexuality as a mental illness, Green argued forcefully in favor of the removal. He argued that the grounds for deciding the issue should be the "historical and cross-cultural groundings in homosexual expression, associated psychiatric features accompanying a homosexual orientation, the emotional consequences to the homosexual of societal condemnation, and behaviors of other species". Green applauded the eventual APA decision while strongly criticizing the fact that the administration put it to a vote, saying that such "a shotgun marriage between science and democracy" was "ludicrous".
Green was co-counsel for Elke Sommer in her libel suit against Zsa Zsa Gabor. He was ACLU co-counsel in a case challenging the Boy Scouts for refusing membership to a homosexual young man. He served on the American Psychiatric Association DSM-IV Subcommittee on Gender Identity Disorders. Green turned over the editorship of Archives of Sexual Behavior in 2002 to Kenneth Zucker. In 2006 he was awarded the Magnus Hirschfeld Medal for Sexual Research.
Green was research director and consultant psychiatrist at the Gender Identity Clinic at Charing Cross Hospital in Londonand Senior Research Fellow, Institute of Criminology, Cambridge and Member of Darwin College, Cambridge. His partner since 1988, Melissa Hines, is a professor of psychology at the Faculty of Politics, Psychology, Sociology and International Studies, University of Cambridge. In terms of research on biology and sexual orientation, Green is optimistic about progress and has told a reporter that "I suspect that at least in your lifetime we will find a gene that contributes substantially to sexual orientation."