People with blood types A and B have babies with blood types that may be A, B, AB, or O. The common clinical classification of blood type is determined by the type of antigen present on the surface of the red blood cells in the blood. A person with blood type A has A antigen on the surface of the red blood cells, and the possible gene types are Ai or AA, while a person with blood type B has B antigen on the surface of the red blood cells, and the possible gene types are Bi or BB. Since the offspring inherits half of the genes of each of the parents, the baby’s gene types may be Ai, Bi, AB, ii. The blood type is dominantly inherited, so the baby may present as type A, B, AB or O. The above blood group classification is the ABO blood group classification, and the RH blood group classification system is also commonly used in the clinic. Clarifying the baby’s blood group in time can facilitate the physician’s treatment in the event of a sudden illness.