If a mother has type O blood and the father has type B blood, there are different possible blood types for their offspring. The ABO blood type of the child depends on the genes inherited from each parent.

• If both parents pass their O gene, then the child will have O type blood.
• If the father passes his B gene and the mother passes her O gene, then the child can have either B or O blood type.
• If both parents are BO (one parent has B and the other has O), then the child can have any of the following blood types: B, O, AB, or A.

It is important to note that these are the most likely outcomes, but there are exceptions to these rules. The ABO blood type of the child can be predicted using a blood type calculator based on the blood types of the parents.