It can also be that one of your parents is O-positive and the other is negative. For example, if your mother is O
and your father is A-negative, than you can be O
-negative, A-positive or A-negative. So you can get the type ( O, A, B, or AB) from one parent and the Rh factor (positive or negative) from the other parent. It is also possible to have the exact same blood type as one of your parents.