Ans. Every biological parent donates one ABO alleles to their child from their available two alleles. A mother who is with a Type - O blood can only pass an O allele to her daughter or son. A father who is with Type - AB blood could pass either an A or a B allele to his daughter or son. This couple (mother and father) could have children of either blood type A (Type-O from mother and Type-A from father) or blood type B (Type-O from mother and Type-B from father).Since there exist four different paternal blood types and four different maternal possible blood types, there are 16 different combinations that are to be considered when predicting the children's blood type. If we know the blood type of our father and mother, possible blood types for their children can be identified.