[5][2] Milton Diamond graduated from the City College of New York with a BS in biophysics in 1955,[1][2] after which he spent three years in the Army as an engineering officer, stationed in Japan.

In 1965 Diamond published "A Critical Evaluation of the Ontogeny of Human Sexual Behavior Archived September 13, 2021, at the Wayback Machine" a critique of Money's work.

[2] Diamond was best known for following up on the case of David Reimer, a boy raised as a girl under the supervision of John Money after his penis was damaged beyond surgical repair during a botched circumcision, which was performed using an unconventional method of electrocauterization instead of a clamp and scalpel.

[12] Diamond wrote 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 was frequently interviewed for public media and legal matters, and often served as an expert in court proceedings, and was known for his research on the origins and development of sexual identity.