Mom is o- baby is o+... what are the possible blood types of the father.

The Father could be Type A, B, or O. Specifically AO, BO, or OO. The RH factor would lead us to assume that he would RH +. So A+,B+,O+.

Why do you ask?

Is this a question of paternity? If so, blood type really means nothing. A DNA test is the only way to determine paternity.

It is not a simple issue, the chart is expanded so, almost any combination can lead to that,

Is this a homework?
Or is it a issue of who a father is?