Rh Factor Inheritance: Can O Positive Parents Have a Negative Child?

Question
QUESTION: Can parents with O positive have a child that is a negative?

ANSWER: Hi Shannon, I'd be glad to try and answer your question.  Yes, there is a 1 in 4 chance that a child with two Rh+ parents can be Rh-.  Being Rh+ is considered a dominant gene, meaning most of the time, the child will be Rh+.  But all there needs to be is one Rh- family member (grandparents, great-grandparents) and the chance is there that a child will be Rh-.  Also, sometimes babies don't produce enough antibodies at birth for the lab to detect and they will be typed as Rh-.  In cases of uncertainity, re-testing at 6-12 months of age will be more accurate.  I hope I've answered your question.  Take care!

**Information contained is not intended nor implied to be a substitute for professional medical advice.**

---------- FOLLOW-UP ----------

QUESTION: What about being an A- blood type with 2 O positive parents?

Answer
Hi Shannon.  Yes it is possible to have an A negative child with two O positive parents.  The Rhesus (Rh) Positive gene is a dominant so if both parents are positive it means they have one Positive gene which 'masks' the Negative gene.
But two Negative parents cannot have a Positive child. This is the same way that two brown-eyed parents can have a blue-eyed child but two blue-eyed parents cannot have a brown-eyed child.