If the father and mother both have blood type B, then the child may have blood type B or O. If the father and mother both have blood type B, then the blood genes for both may be BB or BO. If the blood genes of both father and mother are BB, then the child’s blood genes are also BB, for blood type B. If the blood genes of both father and mother are BO, then the child’s blood genes may be BB, BO, or OO, and then the child’s blood type may be B or O. If one of the father’s and mother’s blood genes is BB and the other is BO, then the child’s blood genes may be BB or BO, and the child’s blood type will be B blood. Therefore, if both the father and mother have blood type B, then the child may have blood type B or blood type O, but the results of the test should be taken into account.