If the blood groups of the parents are this: Father A+ and Mother ARH+, can their female child be blood group O-?
The main blood groups are A and B, but both these groups carry alleles for the O group. It is a recessive trait, as are blue eyes. Just as two parents with brown eyes can have a blue-eyed child, two A+ parents can have an O- child.
The + and - refers to the Rh factor. If a person is Rh+, his offspring can either be positive or negative. However, if a person is Rh-, then the offspring can only be -.