The man couldn’t have fathered the following child.
Step-by-step explanation:
The blood grouping system in humans is called ABO blood grouping. The possible blood groups of humans are A,B,AB and O. ABO blood grouping is an example of co-dominance where both alleles of the ABO gene are expressed equally.
The ABO gene has 3 alleles. They are I^A,I^B and i. the alleles I^A,I^B are dominant over i. Person with the genotype I^A I^A and I^A i has the blood group A while a person having the genotype I^B I^B and I^B i has the blood group B. The person with the blood group will have the genotype I^A I^B.
Here the mother’s blood group is O which means her genotype is ii. The man’s blood group is AB which means his genotype is I^A I^B. The possible genotypes of the children are I^A i,I^A i,I^B i,I^B i with respective phenotypes A, A, B and B.
There is no possibility that the child can have the blood group O which means that the man could not have fathered the child.