Home | Timeline | Men's Info | Personal_ Calendar |Baby_ Names | Health | Genetics | Weight Gain | Picture_Gallery | Books | Shopping(USA) | Shopping(UK) |Multiples |  Pregnancy_ Loss | Forum | Disclaimer | FAQs

Your Questions Answered... 

Back to Questions

Q

If a father is A+ and a mother O+ can a child be born RH negative? I think I read that this is possible.

A

When blood types are quoted, there are two different systems used. The first is the ABO blood typing system which provides the letter (A, B, AB or O). The second system is the RH factor which provides the positive or negative factor of the blood.

This means that the A of the father and the O of the mother is irrelevant when defining the child's RH factor.

When both parents are RH positive (as in your example), then it is perfectly possible for a child to be RH negative. 

Someone can only be RH negative if they carry (and inherited) the negative factor from both parents, but because the positive gene is dominant then it is possible that both parents carry the + - version of Positive (the negative is present but is not expressed because the positive element is dominant) and subsequently both parents pass on the negative element of their blood to the child (in which case the child is RH negative).

If you see the article found at http://www.paternityangel.com/Articles_zone/Blood/BloodType3.htm  then you will notice that the 3rd line in the table shows this possibility.

Back to Questions

.

Home | Men_ &_ Pregnancy | Timeline | Personal_ Calendar | Baby_ Names | Health | Genetics | Books | Pregnancy_ Loss | Multiple_Pregnancies | Forum  | Gallery | Shopping(USA) | Shopping(UK) | Disclaimer | Privacy_ Policy | Glossary | FAQs  

All information provided on this web site is for the purpose of education, information & discussion only and is not a replacement or substitute for consultations with your medical practitioner.  If you have ANY concerns about your health, please see your doctor immediately and do not rely solely on information found here or anywhere else on the internet.