What blood type a person is depends entirely upon the genotypes of both of their parents. So the answer to your question is not simple. It is no and it can be yes. For example if both the parents are of recessive group o then they are pure breeding for o and ALL their offspring will be o group. But if the parents genotypes are mixed ( which would be more likely) then the offspring can differ in groupings. For example mum is genotype Ao and dad genotype Bo. This parental combination can produce types AB, type A, type B and type o. Hope this helps.
