I’m O-positive and my mother is A-positive. She seems to think that that can’t be. I’m not sure so I decided to ask it here because I’m sure that someone can tell me about the genetic issues behind this.
What is your father’s blood type?
Sounds like your mother is Ao. If she were AA, then she couldn’t give you o. Your dad is probably Ao, Bo, or oo. Any of those would allow you a chance for type O (oo) blood.
I don’t know my father’s blood type. Does Ao=A-positive?
Headless, Ao means that your mother carries one dominant A gene (A) & one recessive O gene (o).
A mother who has 2 A genes (AA) can only have a child who is A, or AB, depending on the father’s contribution. A mother who is Ao can have a child with:
m—f---g–ph
A + A = AA = A
A + B = AB = AB
A + o = Ao = A
o + A = Ao = A
o + B = Bo = B
o + o = oo = O
where m=mother, f=father, ph=phenotype, g=genotype…
depending on whether the child gets the A or o gene from her & what gene (s)he gets from the father…
Sue from El Paso
members.aol.com/majormd/index.html
How important is it for a young adult to know their blood type? I am in my early 30’s, single, and don’t know mine.
George,
If you needed blood, a hospital can anaylze your blood in about 5-10 min. So it’s not too important. The best way to find out what you blood type is to donate blood. They will give you a card that lets you know. It one of the easyist way to ‘volunteer’ and can save up to four peoples lives every time you donate.
cmetzb sed to curious george:
If you needed blood, a hospital can anaylze your blood in about 5-10 min. So it’s not too important. The best way to find out what you blood type is to donate blood. They will give you a card that lets you know. It one of the easyist way to ‘volunteer’ and can save up to four peoples lives every time you donate.
*The test actually takes just a few seconds, as it’s often done in ERs.
George, if you’re not in a high-risk group (HIV, hepatitus, etc.), go ahead and donate and keep donating. Along the way you’ll find your blood type.
I’m close to 2 gallons donated now, fortunately not all at once. 
This all started b/c I donated blood. When I got my card and told my mom my blood type she found her card and looked to findout her blood type. Then she thought that it was impossible for an A-positive mother to give birth to an O-positive son. This meant one of two things: Either she was wrong or I was not her child, ie. I had been switched at the hospital. I was hoping that it was the former. She may have been hoping the latter b/c soon my bills for college will start to come in. Anyway, I figured that here would be the best place to ask. Thanks to all who helped!