Can you be medically cleared to box as an amateur or professional with only one functioning kidney? Here's my situation: I've been meaning to get back in the gym and give it another go for a while, but injured myself in a very stupid way a few months ago (broken foot requiring two surgeries and a whole summer in a cast...don't get drunk and jump off a bridge onto a moving train, FYI). That was only a minor setback. I even had a specific gym nearby cased out and was going to sign up in the fall once done with rehabilitation, with the orthopedic surgeon's blessing. However, with timing courtesy of Murphy's law, my girlfriend's brother who was previously on the "might need a donor down the line" list has since been bumped to the "needs one ASAP" list. It's that or go on dialysis, permanently. So I've undergone testing to become a donor candidate, along with some of his relatives. I'm the youngest and healthiest, and am very likely to be picked. My little brother was born with only one kidney - and when he was a baby the doctors pretty much put a lifetime moratorium on any contact sports. They didn't specify boxing, but they explicitly ruled out football for him (so presumably boxing would not be kosher). Fortunately he turned out to be more of a science fiction nerd than an athlete, but it got me to wondering. If I go through with the donation, will that disqualify me from ever competing in a prize ring on medical grounds? That's the only thing that could cause me to have any hesitation (or regrets).