According to the FDA, men who have had sex with men "are, as a group, at increased risk for HIV, hepatitis B and certain other infections." To protect blood recipients from this risk, their blood must be excluded. This kind of group-based screening is a longstanding practice in blood regulation. Over the years, we've prohibited donors on the basis of nationality as well as sexuality. There's nothing wrong with such categorical exclusions, according to the FDA, as long as they make the blood supply safer. But if that's true, why not screen donors by race?
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