Mom has blood type B. The exact blood type of the child will also need to be determined in conjunction with the father’s blood type; type A, B, AB or O are all possibilities. Blood type is a classification based on differences in the same family of antigens on the surface of a person’s red blood cells. Genetically speaking, the genotype of blood type B is BB or BO. There are four different scenarios depending on the dad’s blood type. 1. If the dad’s blood type is A, then the child’s blood type is A, B, AB or O. 2. If dad’s blood type is B, then the child’s blood type is B or O. 3. If the father’s blood type is AB, then the child’s blood type is A, B or AB. 4. If the father’s blood type is O, then the child’s blood type is B or O.