# Blood Types **URL:** \ **Category:** Factual Questions\ **Created:** [July 26, 1999, 9:36pm UTC](https://boards.straightdope.com/t/blood-types/2198 "1999-07-26T21:36:00Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [July 26, 1999, 9:36pm UTC](https://boards.straightdope.com/t/blood-types/2198/1 "1999-07-26T21:36:00Z")
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. ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [July 26, 1999, 9:40pm UTC](https://boards.straightdope.com/t/blood-types/2198/2 "1999-07-26T21:40:00Z")
What is your father’s blood type? ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [July 26, 1999, 10:18pm UTC](https://boards.straightdope.com/t/blood-types/2198/3 "1999-07-26T22:18:00Z")
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. ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [July 27, 1999, 1:43am UTC](https://boards.straightdope.com/t/blood-types/2198/4 "1999-07-27T01:43:00Z")
I don’t know my father’s blood type. Does Ao=A-positive? ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [July 27, 1999, 2:27am UTC](https://boards.straightdope.com/t/blood-types/2198/5 "1999-07-27T02:27:00Z")
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](http://members.aol.com/majormd/index.html) ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [July 27, 1999, 8:28pm UTC](https://boards.straightdope.com/t/blood-types/2198/6 "1999-07-27T20:28:00Z")
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. ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [July 27, 1999, 8:55pm UTC](https://boards.straightdope.com/t/blood-types/2198/7 "1999-07-27T20:55:00Z")
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. ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [July 27, 1999, 9:11pm UTC](https://boards.straightdope.com/t/blood-types/2198/8 "1999-07-27T21:11:00Z")
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. 🙂 ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [July 29, 1999, 3:13am UTC](https://boards.straightdope.com/t/blood-types/2198/9 "1999-07-29T03:13:00Z")
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!