What would be a child's blood type of the mother is O and the father is A?

We are looking for the possible blood types for a father.

Available information:

• Mother type O -- OO can only contribute an O gene
• Baby type A -- has to be type AO since the mother contributes the O

Father contributes the A gene; therefore, his genotype might be:

• AA
• AO
• AB

With a mother type OO and baby type AO, the father would be either type A or AB.