If the mother of a child is blood type O+ and the child is A-, what blood type would the father be? Does the Rh factor of the child being - (negative) mean that one of the parents has to be negative? Both the parents are Rh - all of the siblings are Rh-as well. Could two Rh- parents give birth to a Rh+ child? and visa versa?
The father could be:
(a) A+, A-, or O-
(b) A+, A -, AB+, or AB-
(c) B+, B-, or O-