How would it be possible to cross a man that has Type B blood and a woman who has Type A blood, while their child has Type O blood?

If the parents are heterozygous for type A blod and for type B blood, when crossed, there is a 25% chance teh kid will have type O blood

Explanation: This is possible because there are two genotypes that code for type A and B blood

The genotypes for type A blood are:

I^A I^A or I^A i

The genotypes for type B blood are:

I^B I^B or I^B i

Visual: (Punnett square)

I^A i

I^B I^A I^B I^B i

i I^A i ii

*Remember that the genotype for type O blood is ii

For them to have a type o baby that means the man or woman must have a type o in there family some how to get passes down to the baby