Stem cell transplantation matching, from the perspective of genetic probability, most of the parents odds are greater than the siblings odds.
The human body develops from a fertilized egg, which is a combination of sperm and egg, and is calculated as follows according to genetic probability:
50% of the genes in the human body come from the father and 50% of the genes come from the mother, so the mating rate with the parents is 50%; the probability of mating with the biological siblings is 25%, which is actually higher than this rate. So, if you compare it with an older sibling, in most cases, the chance of being a match for the parent is higher than for the older sibling.
In the specific case, one should go to the hospital and undergo a formal examination for stem cell matching to determine if the match can be made. Therefore, the matching results should be used as the basis.