Until 2015, men who have had sex with another man weren’t allowed to donate blood – and there were still limits on their donations until last year, when the federal government lifted those.

Transplant experts are seeing a spike in people revoking organ donor registrations, their confidence shaken by reports that organs were nearly retrieved from a Kentucky man mistakenly declared dead.

Former Minnesota Gophers and Vikings player Ben Williams went for a routine checkup in June of 2015. He was told that his kidneys were operating at 15% of their normal function. “I consider myself ...