Biogenetically speaking, two people with type O blood can only have a child with type O blood. In the ABO blood group system, the A and B genes are dominant, and the O gene is recessive; because both husband and wife give their children the O gene, the final child can only be of type O, and no other blood type is possible. Blood type O does not contain A antigen or B antigen, so it is also known as universal transfusion; however, if a blood transfusion is needed, blood type O can only accept blood type O, otherwise there is a possibility of a more serious transfusion reaction. Blood type generally does not change, because the blood type of both the mother and the child is O. Therefore, hemolytic jaundice caused by blood type incompatibility can also be avoided during pregnancy. If you have any symptoms of discomfort, you should go to the hospital and consult your physician for guidance.