My parents have O+ and B+ blood and I have O-, isn't that impossible?

Question

I'm not adopted, I have four little siblings and we all look like our parents and each other

How rare is it? And I know it's not impossible I'm saying in theory it should be

Answer 1

You are looking at two markers that are on your blood cells. The first one is the A/B indicator and the second is the Rh.

First the A/B. Ignore the + and - right now. You get one indicator from each parent. So you can get an A from one and a B from the other making you AB blood type. If you get an A and an O (total lack of any indicator) you would be an A blood type.

The O+ parent has no A/B indicator to pass on to you. Your other parent is B+ so they can be BO or BB to have the "B" blood type. Since you are not adopted, they must be the BO type.

For the +/- determination, we look at a different indicator, the Rh indicator. For this one, you either have it or you don't. Since both your parents are "+", they must have either +/+ or +/- since the "+" in the +/- means you have the indicator. For you, you are -/- since you are O-. This means that your parents must both be +/-.

The likelihood of you getting the - blood type is 25% and for O is 50%. This means that the likelihood of you being O- with your parents being O+ and B+ is 12.5% or one in eight.

Answer 2

One parent should have Rh negative if you really have that, but if your father is the one with negative nobody would really have noticed much. If your mother had negative she would probably have been made more aware of it when having you and your siblings. Any chance your father just assumed he had positive because it was never brought up?

Any chance either you or one of your parents have a mistaken blood type when it comes to the Rh factor?

There is also something about O blood that is different. Its a universal blood type and it can go with any of the other blood types in transfusions. You should look up more information on Type O blood because that could give you some answers.

Here's a link that refers to errors in blood typing:

http://experts.about.com/q/Genetics-1795/Blood-Type-RH-factor.htm

Answer 3

Nope, do your Punnent Square over again. It means,
Parent A: o o
Parent B: B o
Well, that gives you two possibilities: B or o. The positive or negative is a bit more complex, but follows pretty much the same principle, so you can indeed be O-.

Answer 4

It is possible as it happens to you, isn't it? It might sound strange but it's true. For the ABO group, your parents have OO and BO and the possible blood group of their children are BO, and OO. The possibility of the kids to have BO to OO is 2:2. For the Rh positive and negative, I really have no idea. I forgot about them.
To tell you this is Biology.

Answer 5

Aliedes carry both parents blood types. One of your parents carried B+ & O aliedes. The B+ dominated in their blood type, both when mixed with O, the O aliede dominated.

Answer 6

Hi,

It is possible.

When you say one of your parent's blood type is B, it is either 'BB' or 'BO'.

When talking about blood types, you inherit your one blood type from each of your parents. So, if you get "O" from both parents, you'll be O.

Same for the RH factors, when your parents both have RH+ factors, they are either RH++ or RH+-. Therefore, you can either be RH+ or RH-...

Please see the website for the inheritance of blood types..

http://www.mistupid.com/health/bloodinherit.htm
http://www.bloodgivers.com/inherit.asp

Answer 7

There is no such thing as OB blood. Babies can be born RH negative. It happens all the time.
If you are hoping to prove that you were adopted, you will have to look somewhere else.

Answer 8

You need to look back further than your parents. It could be the Grands.

Answer 9

It's possible because your grandparents probably had O- blood type. That can happen sometimes. Ask your grandparents.

Answer 10

Have you asked your parents if you were adopted?