If a child's blood type does not match with that of his parents, is that child definitely a stepdaughter?

[BlackStarInSpace]

Mother= ab +
Father= 0 +
Me= 0+

[Anonymous]

Yeah usually. There is a very rare type of ab blood which people who have that special form of ab blood can have children with typ O blood. It’s very rare though and basically only seen in certain groups of Asian people. Normally a AB and O parent can't have an O child.

[Kelly6]

Not true

blood type doesn’t mean anything

[Astarlessnightsky]

Its no proof, the weird thing about DNA and genes in general, sometimes there are recessive gene coming through, resulting in something none of the parents have got.

[rigmarole]

If the mother is AB and the father is O you would be either A or B because the mother is codominate and therefore can't pass a recessive allele.

[rigmarole]

Blood types don't have to match the parent, but the results have to be possible. For example if you have a father that is type A and a mother that is type B, they can have a type AB or a type O child because they each have a dominate allele and each carry a recessive allele. If the two dominates end up together you are AB if the two recessives end up together then you are O. One comes from each parrent.

[CupcakeTheDestroyer]

Mutations happen all the time, it’s not necessarily a sign of adoption

[Anonymous]

No. But the cases of an AB parent and an O parent producing anything other than an A or B offspring is extremely rare.

[In_Trance]

Nope

[TallAnon]

Nope