Often we envision donating our organs after we are dead, but we can also choose to become an organ donor while we are alive if we share part of our liver or donate one of our kidneys.
The proposal to give one of our two kidneys away, though, does raise some ethical and safety concerns. There can be long-term risks for the donor. Donating a kidney, moreover, would not be therapeutic for us —only for someone else — and in fact, might slightly increase our own risk for experiencing renal failure in the future.