Can mother with B negative blood and father with O positive blood have a baby with AB negative blood type?

Answer 1

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

Parental information:

• Mother type B neg -- can be BB or BO and only Rh (--)
• Father type O pos -- can only be OO with Rh (+-) or (--)

Baby recieves one gene from each parent:

• Baby is type BO Rh (+-) = B pos
• Baby is type BO Rh (--) = B neg
• Baby is type OO Rh (+-) = O pos
• Baby is type OO Rh (--) = O neg

NOTE: There is NO A gene for either parent.

Generally the baby will be either Type B pos/neg or Type O pos/neg.

HOWEVER: There is more to ABO blood typing that just the ABO gene.

There is also an inhibitory gene that will change any genotype into the phenotype O.

Therefore a person with genetically AB blood can be tested as having Type O.

• A baby from these parents could be AB neg IF

If one Type O parent has the inhibitory gene affecting his AA, AO or AB type, then the baby can be AB negative.

Answer 2

No. They can have an O positive, an O negative, A B positive, or a B negative child.