Mrs Smith has blood Type A her father has blood Type A and her mother has blood Type B. If Mr Smith has blood Type AB what is the probability that they will have a child with blood Type AB?

We are looking for the possible blood types of a baby.

Parental information:

• Mrs Smith = Type AO = contributes A or O gene
• Her father Type A (AA/AO), Mother Type B (BB/BO)
• Mr. Smith = Type AB = contributes A or B gene
• Baby Type AB(?)

Baby Smith receives one gene from each parent:

• Baby type AA,
• Baby type AB
• Baby type AO
• Baby type BO

The baby has a 25% chance of having Type AB blood.