Mass was born in Macon, Georgia, in 1946, received his B.A. from the University of California at Berkeley in 1969, and his M.D. from the Abraham Lincoln School of Medicine in 1973.
In the late 1970s, Mass had completed his residency in anesthesiology at Boston's Massachusetts General Hospital in association with Harvard Medical School, but the homophobia he encountered when he casually came out as gay during interviews in Chicago for a second residency in psychiatry became the springboard of an activism centered in journalism. Up to that time, though physicians would crop up from time to time in one capacity or another as authors or sources of articles, there had yet to be a physician writing for the gay press on a regular basis.
Mass first entered the scene as a watchdog for reactionary movement in psychiatry. Although this was nearly five years after the declassification of homosexuality as a mental disorder by the American Psychiatric Association (1973/4), psychiatry retained many of its homophobic practitioners, practices, and stances. Along with writing pieces for the gay press, Mass became newsletter editor of the Gay Caucus of Members of the American Psychiatric Association, the fledgling organization of gay psychiatrists that began organizing in the aftermath of the declassification. Under Mass's stewardship, the newsletter ran politically-charged headlines such as its first: "Psychoanalytic Statute Prevents Legal Entry of Gay Aliens," calling attention to the fact that discredited psychoanalytic theories of "the homosexual" as a form of "psychopathic personality" were still sources of pejorative public policies. Most of his writing for the gay press was about how developments outside psychiatry, especially in sociology and sex research, had taken the lead in shaping contemporary thinking about sexuality and homosexuality. As Mass saw it, he was chronicling the shift of the credibility of the best academic and scientific thinking about homosexuality and sexuality "from the temples of psychiatry to the laboratories of sex research." He conducted and published in the gay press many interviews with such leading figures in the discourse as Judd Marmor, Richard Pillard, Thomas Szasz, John Money, Charles Silverstein, Masters and Johnson, Richard Green, Mary Calderone, John Boswell, John D'Emilio and Estelle Freedman, and Martin Duberman. A selection of these interviews are republished in his two "Dialogues of The Sexual Revolution" collections.
In writing for the gay press as a physician, Mass began to move into another and rapidly growing area of concern to the gay community: the epidemic spread of a number of sexually -transmitted diseases, including syphilis, gonorrhea, hepatitis B, amebiasis, and, in 1981, a deadly new disease that would become known the following year as AIDS. Mass wrote the first press report and first feature article, "Cancer in the Gay Community," on the epidemic (among the opening displays of the Newseum in Arlington, Va.), and continued his coverage of AIDS, regularly for the next several years and periodically since that time.
In 1982, Mass joined Larry Kramer, Edmund White, Paul Rapoport, Paul Popham, and Nathan Fain in co-founding Gay Men's Health Crisis (GMHC), the oldest and still the largest AIDS information and service organization. For ten years, through four revisions, Mass wrote GMHC's guide, Medical Answers About AIDS, which usually concluded with an appeal for "the securing of civil liberties for sexual minority persons and the cultural sanctioning of same sex relationships" as "essential considerations in the preventive medicine of AIDS and other STDs."
In the late 1990s Mass became independently involved in another public health initiative: outreach to the bear subculture of the gay community. For many years, he has written a column on the subject of bears and health, initially for American Bear Magazine and subsequently for A Bear's Life magazine, on a wide range of topics of pertinence and interest to a subculture that initially tended to be made up of middle-aged, overweight men.
At the start of the AIDS epidemic, another theme would emerge that was to preoccupy Mass: anti-Semitism. As described on the dust jacket of his memoir, "Confessions of a Jewish Wagnerite";
Mass's entangled concerns re Jews, Jewishness, anti-Semitism, and the internalization of antisemitism provide an unanticipated lens through which to view the subject of the last of his books, his collection on the life and legacies of Larry Kramer.
The anthology,"We Must Love One Another or Die: The Life and Legacies of Larry Kramer", begins with "Larry versus Larry," the story of Mass's sometimes stormy 40-year relationship with Kramer, and includes contributions from a number of key figures from the AIDS movement, including historical and critical evaluations by Rodger McFarlane, Anthony Fauci, Michelangelo Signorile, Gabriel Rotello, Tony Kushner, and John D'Emilio. While Kramer is likely to remain best known for his achievements around AIDS and grass roots activism, it's Kramer's experience as a writer, especially his very personal voice and his bravery and perseverance in the face of harsh criticism and rejection, that seems most to have inspired Mass. Chapters by Andrew Holleran, Christopher Bram, Alfred Corn, Michael Denneny, and others complete the picture of, as the dust jacket puts it, "one of the most original and influential voices of the twentieth century."
By the mid-1990s, thanks largely to the efforts of Kramer and ACT UP, AIDS had become a treatable disease, and gay activist concerns began to shift. Kramer took on the challenge of fighting for a more respectable and appropriate place in academe for GLBT studies and has worked for many years on a magnum opus, the working title of which has been "The American People." Mass has continued to write about newer health problems afflicting gay men: escalations of HIV among minority teens and the elderly, the crystal meth epidemic, hepatitis C, and anal cancer. He is as well continuing his health outreach to the bear community
Mass's papers, and those of his partner, Arnie Kantrowitz, are designated collections of the New York Public Library.