In the United States, men who have had sex with men (even once) since 1977 are permanently disqualified from donating blood.  This rule, adopting by the Food and Drug Administration (FDA) in the mid-1980s shortly after epidemiological studies had demonstrated that whatever was causing AIDS was probably a blood-borne pathogen, but also shortly before the particular viral vector had been shown and well before there was detailed information about how it was transmitted and what … <Read More>