Milton Diamond (born March 6, 1934 in New York City) is a retired professor of anatomy and reproductive biology at the University of Hawaiʻi at Mānoa. He has had a very long and productive career in the study of human sexuality. Dr Diamond retired from the University in December 2009 but continues full-time with his research and writing and also continues to travel extensively consulting in his field.
Early career 
Milton Diamond graduated from the City College of New York with a B.S. in biophysics in 1955, after which he spent three years in the Army as an engineering officer, stationed in Japan. On returning to the United States, he attended graduate school at University of Kansas from 1958–1962 and earned a Ph.D. in anatomy and psychology from that University. His first job was teaching at the University of Louisville, School of Medicine where he simultaneously completed two years toward an M.D., passing his Basic Medicine Boards, and in 1967 he moved to Hawaii to take up a post at the recently-established John A. Burns School of Medicine. Milton Diamond had a long running feud with the psychologist Dr. John Money. In the early seventies, Diamond and Money were attending a conference on transgenderism in Dubrovnik. According to the book As Nature Made Him: The Boy raised As A Girl (p. 174) at this conference Money initiated a loud and aggressive argument with Diamond. One witness claims that Money punched Diamond; however, Diamond himself said that he could not recall any physical contact during this encounter.
The "John/Joan" case 
Dr. Diamond is known for following up the case of David Reimer, a boy raised as a girl after a botched circumcision. With the cooperation of Dr. H. Keith Sigmundson, who had been Reimer’s supervising psychiatrist, he tracked down the adult Reimer and found that John Money’s sex reassignment of Reimer had failed. This case, which Dr. Diamond named that of "John/Joan" to protect Reimer’s privacy, has become one of the most cited cases in the literature of psychiatry, anthropology, women's studies, child development, and biology of gender.
The major tragedy of the decision to raise David Reimer as a girl is that it was popularized as a success. This was unfortunately accepted by physicians as a model for how to deal with infants with intersex conditions. Dr. Diamond was the first to alert physicians that the model was faulty. He recommended that physicians (1) do no surgery on intersexed infants without their informed consent; (2) assign such infants in the gender to which they will probably best adjust; (3) refrain from adding shame, stigma and secrecy to the issue, by assisting intersexual people to meet and associate with others of like condition. Dr. Diamond encouraged considering the intersex condition as a difference of sex development, not as a disorder.
Current work, appointments and awards 
Diamond has written extensively about abortion and family planning, pornography, intersexuality, transsexuality, and other sex- and reproduction-related issues for professional sex and legal journals, as well as lay periodicals. He is frequently interviewed for public media and legal matters, and often serves as an expert in court proceedings, and is known for his research on the origins and development of sexual identity. Although he has retired from teaching, he continues to research and consult concerning transsexuality, intersexuality and pornography.
Dr. Diamond was based at the John A. Burns School of Medicine, now at the University of Hawai'i at Mānoa, from 1967. He was appointed Professor of Anatomy and Reproductive Biology in 1971, and from 1985 until his retirement he was Director of the Pacific Center for Sex and Society within the School of Medicine.
Awards which have been made to Dr. Diamond include:
- 1999: the British GIRES Research Prize
- 2000: the German Magnus Hirschfeld Medal for sexual science
- 2005: the Norwegian Diversity Prize for his research efforts on behalf of transsexual and transgender people worldwide
- 2008: the first of a proposed annual award made by the German Intersex Society (Intersexuelle Menschen e.V.) "for his decades-long commitment to the benefit of intersex people";
- 2009: the Regents' Medal for Excellence in Research by the University of Hawai'i;
- 2010: the Kinsey Award for 2011, made by the Midcontinent Region of the Society for the Scientific Study of Sexuality.
- Sexual decisions (1980) - ISBN 0-316-18388-1
- Sexwatching: Looking into the World of Sexual Behaviour (1992) - ISBN 1-85375-024-7
- Sexual Behavior in Pre Contact Hawai’i: A Sexological Ethnography
- "Scientific Advisory Board". Archive for Sexology. Retrieved 16 September 2009.
- "An Introduction to Professor Milton Diamond Ph.D.". Changeling Aspects. Retrieved 16 September 2009.
- Colapinto, John (2000). As Nature Made Him: The Boy Who Was Raised As a Girl. HarperCollins. ISBN 0-06-092959-6
- "Sexual Identity, Monozygotic Twins Reared in Discordant Sex Roles and a BBC Follow-Up". Milton Diamond, Ph.D. Retrieved 1 August 2011.
- Diamond, Milton; Sigmundson, H. Keith (October 1997). "Management of intersexuality. Guidelines for dealing with persons with ambiguous genitalia.". Arch Pediatr Adolesc Med. 151 (10): 1046–50. doi:10.1001/archpedi.1997.02170470080015. PMID 9343018. Retrieved 24 April 2013.
- Diamond, Milton; Beh, Hazel. (2008). "Changes In Management Of Children With Differences Of Sex Development.". Nature Clinical Practice: Endocrinology & Metabolism 4 (1): 4–5.
- "Meeting History". International Academy of Sex Research. Retrieved 15 September 2009.
- "Society Presidents". The Society for the Scientific Study of Sexuality. Retrieved 15 September 2009.
- "Past awards for research". Gender Identity Research and Education Society. Retrieved 24 November 2010.
- "Archive for Sexology". HUMBOLDT-UNIVERSITÄT ZU BERLIN. Retrieved 11 November 2009.
- "Intersexuelle Menschen e.V.". Retrieved 15 September 2009.
- "Zwischengeschlechtliche ehrten Milton Diamond". Zwischengeschlecht.info. Retrieved 15 September 2009.
- "Regents' Medal for Excellence in Research awarded to outstanding UH faculty". University of Hawai'i System. Retrieved 15 September 2009.
- "Kinsey Award". The Society for the Scientific Study of Sexuality. Retrieved 1 August 2011.