Try reading up on the match rates.
Yes, cord blood allows a 6/8 match on immune system markers to proceed; but you still have to do a preliminary typing, and a lot of those don’t pan out.
Matching to minorities such as African Americans is particularly hard to accomplish.
“Matching to minorities such as African Americans is particularly hard to accomplish.”
Would stem cells from the umbilical cords of AA babies be more likely to match that group?