If a man of blood-group AB marries a woman of blood-group A whose father was of blood-group O, the expected phenotypes of their children will be as follows:
Woman genotype would be IA/i whereas the genotype of man would be IA/IB. The possible genotypes and phenotypes for their progeny could be
| Genotype | Phenotype |
| I A /I A | A |
| I A /I B | AB |
| i/I A | A |
| i/I B | B |