Michael was raised Mormon, received a full scholarship to University of San Francisco for medicine and converted after his psychiatry degree.
An openly gay man before he converted to Catholicism and became a priest of the Archdiocese of Washington; he was the founder of the St. Luke Institute (a psychiatric hospital in Maryland for Catholic priests and religious-order men and women) and the co-author of a 1985 report to U.S. Catholic bishops, warning them about the level of sexual abuse by priests.
"His report was dismissed by US bishops. Some may have thought he was touting for business for his clinic. Others regarded him as extreme. The report reads now like prophecy."
("Hundreds sue Vatican over child sex abuse", The Sydney Morning Herald, April 6 2002)
He is the founder of the Gay Community News in Boston. Peterson was also one of the first priests with AIDS to attract national attention. He died of AIDS-related complications.