Blood type answer Yes it is possible. Each person has two copies of the gene for blood type (one from mom, one from dad) and gives one of those two copies to the baby. There are three possible genes for those two positions: A, B, O. If you have A and O, you will be A; if you have B and O, you will be B. So it is possible for Mom to have type A and really be genes A,O and give baby her O gene, while Dad has blood type B with genes B,O and also gives baby his O gene, making baby O,O or type O.