Guillermo Mac Millan

Guillermo Mac Millan (born 1940/1941) is a retired Chilean urologist who worked at Van Buren Hospital in Valparaíso. He carried out sex reassignment surgery on hundreds of patients over the course of his career.

Life Mac Millan studied at the University of Chile, where he participated in heart transplantations led by Jorge Kaplán Meyer. He began practice as a urologist in 1966.

In 1976, when Mac Millan was 36 years old, a woman he had operated on for kidney cancer asked him if he could help her daughter, who was a trans woman. Using a modification of an existing technique, Mac Millan performed sex reassignment surgery on the woman's daughter. By the time a year passed, he had performed ten such surgeries, all of them for free. He initially faced criticism from colleagues, who told him that what he was doing was unnatural or immoral.

Between 1976 and 2019, Mac Millan carried out sex reassignment surgery on 448 to about 700 patients. He had many patients from Argentina, where genitoplasty was at one time considered a mutilation punishable by imprisonment,

Retirement Mac Millan retired in 2019 at the age of 78.