Hemolysis does not necessarily occur when the father has blood type O. Hemolysis mainly depends on the blood type of the mother and the child. Hemolytic disease is usually caused by immune hemolysis due to the incompatibility of the mother’s and child’s blood groups. The mother’s blood group antibodies pass through the placenta and cause the destruction of the child’s red blood cells, resulting in hemolysis. There is no obvious relationship between hemolysis and the father’s blood type. Hemolytic disease is closely related to the mother’s blood type. A mother with type O blood and a child with type A or B blood is prone to ABO hemolytic disease. If the mother is Rh-negative and the child is Rh-positive, the child will be prone to Rh hemolytic disease after birth. Therefore, there is no obvious relationship between the occurrence of hemolytic disease in newborns and the father’s O-type blood. When hemolysis occurs, it is important to go to the hospital.