Blood typing can often be used to determine biological fatherhood. Three men, X, Y, and Z, are all possible fathers for child with bood type B. Blood testing determines that the mother's blood type is O. Which blood type must a candidate father have to be eliminated as a possible father?
Explanation
Answer: A, A blood type. If the mother’s blood type is O, the child must inherit the B blood antigen and blood type from its father. In this scenario, the father must have a B or AB blood type.
Key Takeaway: Blood type is inherited from both parents. A and B blood type are co-dominant over O blood type. Therefore, if one parent has O blood type, the child will receive the blood type based solely on the other parent. In this scenario, if the child’s blood type was A instead of B, the child’s father would have to have either A or AB blood type.
