Question

What should be the blood types of parents if their children can have only A and B types of blood

• A. AB and A
• B. A and O
• C. A and B
• D. AB and O

Answer 1

Answer: (D)

If children have A and B blood groups this means that their genotypes are I${}^A$/I${}^A$ or I${}^A$/I${}^O$ for A child and I${}^B$/I${}^B$ or I${}^B$/I${}^O$ for B child. These two blood groups can be formed only if parents have genotypes I${}^A$/I${}^B$ and I${}^O$/I${}^O$. The cross between these two genotypes of parents can only give rise to children with both A and B blood groups.

I${}^A$/I${}^B$ X I${}^O$/I${}^O$

I${}^A$/I${}^O$ and I${}^B$/I${}^O$

So, the correct answer is 'AB and O'