> Races don't exist on any biological level.

You sure about that?

https://www.nmdp.org/get-involved/join-the-registry/ethnicit...

> Finding the right donor for a patient isn’t simple. Donors and patients are matched largely based on genes called human leukocyte antigens (HLAs). These genes code for proteins—or markers—found on most of the cells in your body. When it comes to matching HLA types, a patient’s ethnic background is important in predicting the likelihood of finding a match. That’s because HLA is inherited. Some ethnic groups have more complex tissue types than others, which makes finding a close match more difficult.