Mother, father, and first-degree relatives could be matches, especially if the parents are related. However, while outcomes using a fully compatible mother or sibling are comparable, it is not clear if using a compatible father or non-immediate relative is better than using a partially compatible (haploidentical) mother (
see reference). In fact, there is evidence that a haploidentical BMT, that is from a partially compatible family member, might be as good as that from a fully matched sibling. Haploidentical BMT, in general, is also preferable (and less expensive) than using unrelated donors, cord blood banks or seeking further pregnancies to deliver a healthy matched sibling.