Can a mother with A+ (A positive) blood type and a father with O- (O negative) blood type have a child with AB- (AB negative) blood type?

No, an A+ mother and O- father cannot have an AB- child. This is genetically impossible based on blood type inheritance patterns. Blood types follow specific inheritance rules where A and B are codominant alleles, and O is recessive to both. For a child to have AB blood type, they must receive an A allele from one parent and a B allele from the other parent. Since the father has O blood type, he only has O alleles to contribute (OO genotype), and cannot provide a B allele. The mother with A+ blood type has at least one A allele but no B allele to pass on. Therefore, their children could only have either A or O blood types, depending on which alleles they inherit. The Rh factor (positive or negative) is inherited separately, so their child could be either Rh-positive or Rh-negative, but the blood type itself could never be AB. If an AB- child is born to a mother claiming to have A+ blood type and a father with O- blood type, this would indicate non-paternity or a mistake in blood typing.