If one parent has A positive blood and the other O what type will baby have?

If one parent has A positive blood type and the other has O blood type, the possible blood types for their offspring are A positive, A negative, O positive, and O negative.

This is because the A positive parent can contribute either an A or an O allele, and the O parent can only contribute an O allele.

Therefore, the possible combinations are AO (A positive), AA (A positive), BO (O positive), and OO (O negative).