MICROANATOMY

Detailed explanation-1: -In this particular example, the father has blood type A (genotype AO) and the mother has blood type B (genotype BO). This mating type can produce children with each of the four possible ABO phenotypes, although in any given family not all phenotypes may be present in the children.

Detailed explanation-2: -But it is technically possible for two O-type parents to have a child with A or B blood, and maybe even AB (although this is even more unlikely). In fact, a child can get almost any kind of blood type if you consider the rule-breaking exceptions.

Detailed explanation-3: -In most cases, an O parent and an AB parent will have only A or B kids. I added a table at the end of this answer that has all blood type combinations for two parents plus the possible blood types for their children. Exceptions to these rules are extremely rare.

Detailed explanation-4: -What blood type is NOT possible for an offspring of AO and BO mating? D-A mating between AO and BO persons can result in an offspring with a blood type of A, B, AB, or O. The alleged father of a child in a disputed case of paternity is blood group AB.