Should an altruistic organ donor be allowed to restrict their donation to a specific group of people? (e.g. women, gingers)
An extreme version of this is: What should the German health service do if someone says they are willing to donate a kidney as long as it doesn't go to a Jew?
On the one hand, nobody is forced to donate a kidney and by forbidding this we're making things worse for an innocent patient. On the other hand, it can be seen as the state sanctioning this kind of discrimination.
Being ginger is not a protected class, so there is no legal restriction on descriminating (so long as you don't successfully argue that gingers are a race, eg Scottish, but that's a stretch).
However morally no, you shouldn't have a say in it. Either way, usually you'll be dead when the decision is made. Maybe not with kidneys, although with kidneys you tend to know who you're giving it to - I don't think anyone just randomly donates a kidney, like you would give blood.
I don’t think anyone just randomly donates a kidney, like you would give blood
You would be wrong about that, in 2021 more than 450 people in the US anonymously donated a kidney to a non-familiy member (source). This is the scenario I'm asking about. One of the arguments given is that just as we allow monetary donations to specific groups of people, why not organs.
Nobody knew your scenario before you explained it in detail. It is simply not happening.
Organisations don't want to be bothered with such restrictions from a donor. Their principles are: fair and anonymous. It is hard enough already this way.