A man has type B blood and a woman has type AB blood.  Can they produce a child with type O blood?"  Is a type O possible in this situation?
A.  Possible  
B.  Not possible

Solution:

A man with blood type B and a woman with blood type AB cannot produce type O blood. The reason for the condition is that each parent should donate one of its genotype to the offspring. Generally the genotype for blood B of a man should be homozygous BB or heterozygous BO. Similarly, the genotype of the woman with AB will always holds heterozygous genotype AB. When a cross happens between both the parents the resulting offspring will be A, B, or AB blood type. There is no chance for O blood type as one of the parents lack the genotype O to share with the partner, which is very much needed to produce offspring with blood type O. Lets see in brief the details of the genotypes pertaining to a particular blood type as well as the punnet’s square to understand the details explained above better.

• Blood group A holds the genotype AA or AO
• Blood group B holds the genotype BB or BO
• Blood group AB holds the genotype AB
• Blood group O holds the genotype OO