Should doctors be able to help create a sibling with the same genetic matching to a singling that is already alive for the purpose of using that child as a donor for the sick sibling?

Is it ethical to engage in a process in which you are creating a child for the sole purpose of saving another?

Is it unethical to save a child if you can? Would this be a gray area?

Last time o covered this topic here in CC it was from the angle of the parents and the donor sibling themselves. I have since come to learn that doctors can actually specialize in this genetic matching specifically for this reason. So now I wanted to debate based on medical ethics.