Blood group, mother group A, father who is blood group B but child is 0?

Question

A woman, who is blood group A, claims that her child was fathered by a man whose blood group is B, but he says that this is impossible because the child has blood group O. How is this possible?!

Answer 1

Both parents are heterozygous for their blood type:

Mother:  Ao

Father:  Bo

Child: OO

Possible offspring from these 2 parents are AB, AO, BO, and  OO

(Type O is recessive to both type A and type B)

Answer 2

Guy above is correct. You actually have 2 letters for your blood type AO etc

Answer 3

An individual cannot belong to blood group A, B, or AB, unless the specific characteristics of these groups are present in the parents, whereas the recessive characteristics of blood group O can occur if the parents belong to any one of the four groups. If both parents belong to group O, then the children never have the characteristics of A, B, or AB. The children must then likewise belong to blood group O. If one of the parents belongs to group A and the other to group B, then the child may belong to group A or B or it may possess both characteristics and therefore belong to group AB. If one of the parents belongs to group AB and the other to group O, then in accordance with Mendel's law of segregation the AB characteristic can be segregated and the components can occur as separate characteristics in the children. If a child has the A-group structure (either A or AB), then the A-group characteristic must be present in at least one of the parents, i.e. one of them must belong to group A or AB. If the child belongs to group AB, then one of the parents must belong to group A and the other to group B, or one of the parents must belong to group AB and the other to group A or B, or else both parents must belong to group AB. Application of the discovery of blood groups in questions relating to the establishing of paternity is based on these principles governing the hereditary transmission of blood groups.

A blood-group determination can, in fact, never establish paternity, but can exclude the possibility of it. However, a blood-group determination does not give results suitable for use as evidence under all circumstances. If the child in question belongs to blood group O, then a determination of the group gives no proof, because the recessive blood group in the child provides no basis for any conclusions regarding the parents, who in this case can belong to any one of the four blood groups. Only in those cases where the child belongs to a dominant blood group, i.e. A, B, or AB, and the specific blood structure of the group is not present in the mother, are the results of any value.

Answer 4

It was the milkman wasnt it?

Answer 5

woman: AO

man: BO

child possible blood group: AB, AO, BO, O