Children of parents with blood type B can have blood type O. The difference in blood types is influenced by the law of inheritance of blood types.
Human blood type is related to three genes, A, B and O. The A and B genes are dominant and the O gene is recessive. If the parents have blood type B, the genes for their blood type are BB or BO, and the genes for the child’s blood type are one from the father and one from the mother, so the genes for the child’s blood type can be OO, BB or BO.
If the gene for the blood type is OO, the blood type is O. If the gene for the blood type is BO or BB, the child has B blood. There is a 25% probability of being O and a 75% probability of being B.
The classification of ABO blood type is based on the cohesinogen on the cell membrane of red blood cells. Human blood type has lifelong invariance and heredity, but heredity is affected by the blood type of both parents, and it is normal that the blood type may be different from that of both parents.