How it is possible that blood group shows that a person is not the son or daughter of their parents?

How it is possible that blood group shows that a person is not the son or daughter of their parents?

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I see a family in which it has only one daughter. The blood group of the mother is AB positive and the father is B positive, but the blood group of the daughter is O negative.

When she was young, they apply to shift abroad permanently. When the Embassy test their blood group, the doctor said "She is not your daughter because of her blood group".

How is it possible? Why is she not the daughter of their parents?

Each person has two alleles for the blood type. The two A and B alleles are dominant. So, you don't need A/A to end up with blood type A, it could also be A/O. Having both A and B results in blood type AB. Having none of these, results in blood type O.

Following these rules, from parents being AB and B (genetically either B/B or B/O) you would expect these possible blood types for their children: - A/B - A/O - B/B - B/O

The Rh factor (positive or negative) is inherited similarly. The positive allele is dominant, so genetically +/+ or +/- would be positive, only -/- is negative.

There is a rare case of a "cis AB" mutation, where the A and B antigens are in just one allele (wiki, paper). Then the genetic alleles of an AB type could be AB (in one allele) and O. The children of the couple could then be - AB/B - AB/O - B/O - O/O

So, there would be two possibilities for the case you describe.

  1. The parents are not the biological parents of the child.

  2. The mother is cisAB/O +/- and the father B/O -/-

edit: or a third way would be of course some de novo mutation in the child, resulting in the loss of A/B from the mother

edit2: maybe to answer your actual question "How can a child not be the child of its parents?"… adoption, in-vitro fertilization with donated eggs and/or sperm from other people, mix-up in the hospital…

Using Blood Typesas a Cheap Paternity Test

The earliest paternity test was a comparison of blood types. This analysis cannot provide absolute proof of fatherhood. But it can often eliminate a potential father.

Plus, you may already know each person’s type from medical records. In that case the cost is zero.

TIP: If a man was ever in military service, his type will be on his dog tags.

Even if you don’t already have this information for everyone, this approach may be less expensive than a DNA paternity test.

So you may want to identify the missing blood types before you incur the expense of a DNA paternity test.

Briefly, here’s how blood typing works.

There are four common values: A, B, AB, and O.

If you know the mother and child’s type, then you can use the following chart to narrow the list of possible types for the father.

Find the child's value in yellow and the mother's value in blue. Read down the child's column and across the mother's row to find the green cell where they intersect.

The letters listed in that cell are the possible ABO groups of the father.

For example, if the child is A and the mother is O, the father MUST be A or AB. It is biologically impossible for a man with B or O blood to have fathered this child.

NOTE: The two blank cells represent impossible combinations between mother and child, regardless of the father.

Important Limitations of Blood Types

As you can see in the chart, there are some combinations of mother and child that show all four possibilities and cannot, therefore, eliminate any possible father.

The most important limitation is that knowing this information can, at best, only eliminate someone. By itself, it cannot prove that any given man is the child's father.

However, if the mother knows there are only two possible candidates, eliminating one of them will tell her that the other one is the father.

If this doesn’t resolve the question—-or if you need a positive paternity test for legal purposes—-you must still get a DNA paternity test.

While many companies can provide such a test, the one I am most confident in isꃪsyDNA.

TIP: If your paternity issue involves child support or custody issues, you need to order their LEGAL paternity test that is court admissible. If this knowledge is just for personal information, the home test kit is sufficient.

What if the Father is Unknown?

In some cases a child's biological father may be an unknown man. In that case DNA testing can solve the mystery, just like it has for thousands of adoptees. Read my page on Find Birth Parents to learn more.


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How it is possible that blood group shows that a person is not the son or daughter of their parents? - Biology

When two people share the same H uman L eukocyte A ntigens (abbreviated as HLA ), they are said to be a "match", that is, their tissues are immunologically compatible with each other. HLA are proteins that are located on the surface of the white blood cells and other tissues in the body.

There are three general groups of HLA , they are HLA-A,HLA-B and HLA-DR. There are many different specific HLA proteins within each of these three groups. (For example, there are 59 different HLA-A proteins, 118 different HLA-B and 124 different HLA-DR!) Each of these HLA has a different numerical designation, for example, you may have HLA-A1, while some one else might have HLA-A2.

In the diagram below we can see how a child inherits one HLA in each group, from his/her parents.

If two children inherit the very same HLA from their parents, they are an HLA "identical match". While another child in the same family can inherit a different combination of HLA :

It is important to know that HLA is inherited as a "set" of the three HLA groups, A, B, DR. This set is known as a "haplotype". Below you will notice the father has 2 distinct HLA haplotypes.

This child does not match at all with his/her sibling.

You inherit one haplotype from each parent. Therefore, there are a total of four different haplotype combinations from 2 parents.

There is a basic rule in HLA inheritance. The rule is: you have a 25% chance of inheriting all of the same HLA (same 2 haplotypes) as any one of your siblings, you have a 25% chance of not inheriting any of the same HLA (none of the same haplotypes) and you have a 50% chance of sharing I haplotype with your siblings. Therefore, you have a 1 in 4 chance of being an identical match with your siblings.

After HLA is determined, there is a second test which will indicate if there is specific immune reactivity between the donor and recipient. This test is the "crossmatch".

The crossmatch is a test which determines if the recipient has antibody to the potential donor. Antibody is a protein, present in the serum, which could injure the donor's cells by attacking the HLA . The antibody will only injure the donor's cells if it is specific for the donor's particular HLA Not everyone has antibody against HLA .

The crossmatch is performed by mixing a very small amount of the patient's serum with a very small amount of the potential donor's white cells . If the patient has antibody to the donor's HLA , the donor's cells will be injured and this is referred to as a "positive crossmatch". A positive crossmatch is a strong indication against transplant, since it signifies that the patient has the ability to attack the donor's cells, and would, most likely attack the donor's implanted kidney.

Notice how the patient's antibody fits the donor's HLA just as a lock and key. This means that somehow, the patient has developed an antibody to the donor's HLA type.

There could be any number of reasons why the patient could have antibody to the donor's HLA . The most common causes of HLA antibody production are: transfusions, transplants and/or pregnancies. So, we hope the crossmatch will be negative. A negative crossmatch indicates that the patient does not have HLA antibody against that particular donor, and a transplant can be performed.

Since a patient can develop antibody after a transfusion, it is very important to submit a blood sample to the Tissue Typing Laboratory no later than 7-14 days after each transfusion.

At any time, a patients may request a kit (tube and packaging material) from the lab, for a posttransfusion sample. It is extremely important to inform us each time that you receive a transfusion . This will help us to keep track of your

post-transfusion antibody levels (your PRA ).

PRA ( P ercent R eactive A ntibody) is the amount of HLA antibody present in a patient's serum. As stated before, the patient could have HLA antibody as a result of transfusions, prior transplants, and/or pregnancies. The PRA is determined by testing the patient's serum to a panel of 60 different types of HLA . If, for example, the patient's serum reacts with 30 out of 60 HLA , then the patient's PRA is 50% (1/2 of 60). The PRA is calculated for each monthly serum sample.

In addition to determining how much or how little PRA a patient has, we need to know how specific the antibody is. That is, is the antibody specific to a particular HLA . For example, if you received a transfusion from a donor with HLA-A2, you may develop antibody to A2. That's antibody specificity. Some patients have one or two antibody specificities, while others have numerous specificities. We are able to determine the specificity at the same time which we test for the monthly PRA .

Therefore, the monthly PRA gives us two very important pieces of information about the patient's serum:

Since HLA antibody can "come and go", it is important to test for the PRA regularly. For this reason, we mail a tube to the patient, for a blood sample, on a monthly basis. Monthly testing not only gives us a continuous "look-see" at the patient's HLA antibody , but it also gives us an array of samples with which we can perform crossmatches for each specific donor. The most recent monthly sample is used as the current sample, and must always be included in the pretransplant crossmatch.

Most frequently asked questions

Yes. HLA antibody levels can be high following a transfusion but then decrease significantly months later.

2. Why do I need to submit a monthly sample if I have not received a transfusion?

Sometimes, a patient can have antibody that mimics HLA antibody . Even though it is not harmful antibody , it is difficult for us to determine the cause of the antibody production. Sometimes, even a strept throat infection can cause antibody production which can be confused with HLA antibody . So, it is important for us to monitor monthly serum samples and correlate the antibody production with medical events - such as infections, medications, etc.

3. If my sibling and I have the same blood group, then why wouldn't we have the same HLA ?

The ABO blood group genetic system and the HLA genetic system are not inherited together. So, just as your gene (the DNA ) for eye color is separate from your gene (the DNA ) for your blood group, so is your DNA for HLA . All of these genes are inherited independently from each other.

4. What are the chances of my cousin or even a friend being a match?

Clearly, the further apart a potential donor is from your immediate family, the less likely they are to be an identical match. In the case of cousins, your chance of being identical is "1 in 16". In the case of a friend, then your chances vary depending on how common your HLA is.

We hope this booklet was helpful in your understanding of HLA matching and antibodies. Your tissue typing laboratory staff is always willing and enthusiastic to respond to your questions and concerns.

If you have any questions or would like a further explanation of any of the test procedures? please do not hesitate to call us at (313) 647-2774.

Cynthia A. Schall, (CHS)ABHI James R. Baker, Jr., M.D. Supervisor Director

antibody - A protein, present in the serum, which could injure the donor's cells by attacking the HLA. (pg. 9)

Antibody Specificity - Antibody specific to a particular HLA. (pg. 14)

Crossmatch - A test which determines if the recipient has antibody to the potential donor. (pg. 9)

Haplotpe - A set of HLA which are inherited from a parent. (pg. 6)

HLA (Human Leukocyte Antigens) - Proteins located on the surface of the white blood cells and other tissues in the body. (pg. 2).

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Is there any possibility to change our type of blood? Harry13 May 29, 2010

My mum's blood group is O+ dad A+.. son is O+. Is this possible? From what I read and understand, it's the norm to have the same type bloop group as the dad. anon63507 February 2, 2010

can a baby's blood tell who the father and mother are without the father's and mother's blood? wilfredsmy January 23, 2010

when explaining blood groups, + and - is used for rhesus factor, but sometimes 1 or 2 is used. why? anon60685 January 15, 2010

For all you people wondering about your own or a child's blood type: In a nutshell, a child with parents who both have dominant blood types (A, B, or AB) could inherit the recessive O. It's hidden in the parents, but it's still there. But a child with parents who are both type O cannot (in theory) have a child with a dominant blood type. anon56883 December 18, 2009

I am A positive and Hubby is A negative. Two of my children are A positive and the other is A negative. Up until he went to donate blood and they have said he is AB negative (he is over 40). How can it change? He has been retested and it still comes back AB negative!

Over the years of playing football he has had many test and they were always A negative.

Using a Punnet Square is good, but what percentage would you guess at it being totally wrong? anon52173 November 11, 2009

Answering #96: Yes, this is possible.

Going back to genetics the blood groups of your parents would look like this, using a Punnet Square:

What this means is your parents carry the genes for both A and O type blood. There is a 25 percent chance these will give AB blood (like your brothers) and a 25 percent chance they will give O blood (like yours). anon49998 yesterday

My father is type A and my mother is type B. My four brothers are type AB. why is it that my blood type is O. Is this possible? anon46264 September 23, 2009

If everyone is really so concerned about how their family members' blood types match up, just draw a good ol' Punnett Square. Basically, you have to know what two blood type genes are being carried by each parent. The possibilities are A, B, and O, and each parent will have 2 of those in combination: A parent: A/A or A/O (I'd assume A/O, just to make it easier.) B parent: B/B or B/O (I'd assume B/O, just to make it easier.) AB parent: A/B O parent: O/O Once you've decided what blood type genes the parents carry, draw a 2x2 square. Put one parent's two letters along the top of the square, and those of the other parent down the left side. I'll use my own parents (B father, O mother) as an example: __O__O_ B|__|__| O|__|__| Then, just go row-by-row and match up the letters: __O__O_ B|BO|BO| O|OO|OO| The combinations inside the square are the possible combinations for the blood type of any children they may have. O is always recessive, so BO or AO means the child will have B or A blood, respectively. OO naturally means O blood, and AB obviously means AB blood. Thus, for the example of my parents, the possible blood types of their offspring are either B (the BO combination) or O (the OO combination). And sure enough, my blood type is B. anon46261 September 23, 2009

@83: It's a very odd way of phrasing it, but I assume this woman means that she inherited a positive Rh factor from one parent, and a negative from the other. Assuming that is the case, she has both positive and negative *genes*, but her blood is positive. anon46258 September 23, 2009

The most important part (in summary):

2 Type-A parents. can produce A or O children.

1 Type-A parent, 1 Type B parent. can produce AB, A, B, or O children.

1 Type-A parent, 1 Type AB parent. can produce AB, A, or B children.

1 Type-A parent, 1 Type O parent. can produce A or O children.

2 Type-B parents. can produce B or O children.

1 Type-B parent, 1 Type-AB parent. can produce AB, A, or B children.

1 Type-B parent, 1 Type-O parent. can produce B or O children.

2 Type-AB parents. can produce AB, A, or B children.

1 Type-AB parent, 1 Type-O parent. can produce A or B children.

2 Type-O parents. can only produce O children. @79: I think you're the one who needs to work on their knowledge of genetics. Go read post no. 28. It specifically states that your example is impossible. We don't just magically carry every blood type that has ever been expressed in our family. We've all got two - and only two - blood type alleles, one from each parent. (Rh factor is determined at a separate spot in our genes.) Since there are three possible allele types (A, B, and O), we're all missing at least one of them. Type A people can have: 2 As 1 A, 1 O Type B people can have: 2 Bs 1 B, 1 O Type AB people can only have: 1 A, 1 B Type O people can only have: 2 Os We each pass on *one* of our two alleles (selected essentially at random) to our offspring: AB people can pass on A or B. A people with 2 A alleles can only pass on A. A people with 1 A and 1 O can pass on either. B people with 2 B alleles can only pass on B. B people with 1 B and 1 O can pass on either. O people can only pass on O. The combination of that allele with the allele passed on by our partner determines the baby's blood type. The theoretical combinations work like this: 1 A, 1 B gives the child AB. 1 A, 1 O gives the child A. 1 B, 1 O gives the child B. 2 As gives the child A. 2 Bs gives the child B. 2 Os gives the child O. Therefore, a type B mother can pass on B, and theoretically O if she has a B/O combination herself. A type O father can *only* pass on O. So, your example of a B mother and O father only has two possibilities: type B children (B from the mother, O from the father) or type O children (O from the mother, O from the father). That couple cannot ever produce type A children. Take me, for example. My mother is O, my father is B. I all three of my siblings are also type B, either because my father had a B/B combination or because he had B/O and just happened to always pass on his B allele. anon43891 September 2, 2009

do all blood brothers and sisters have the same blood type or can one have a different blood type? anon42885 August 24, 2009

I know a woman that says that she has positive and negative blood. Is that possible? anon39832 August 4, 2009

The gene that determines your blood type expresses itself as all of the options (A,O,B, etc) in your sperm/eggs. Mother with B, and Father with O can certainly have a child with type A! For example a grandparent on each side could have A!

I have been typed 4 times in my life. Twice it came up as O+ and twice it came up as O-.

It is not one of those things I really worry about, but it is something I would like an answer too. catherine March 6, 2008

There are numerous factors in calculating blood types and unfortunately we cannot provide that specific service here at wiseGEEK. We are, however, committed to providing general information about the topic which should help answer your questions. But, you can type "blood type calculator" into your search engine and you should get several easy-to-use options to calculate specific blood type possibilities!

Here are some general points though. There are two main categorizations of blood type to consider when you're talking about how it is passed on: (1) the blood type (i.e., A, B, AB, and O), and (2) the Rhesus (Rh) factor (i.e., positive (+) or negative (-).

People with type A blood can pass on either A or O.
People with type B blood can pass on either B or O.
People with type O blood can pass on only O.
People with type AB blood can pass on either A or B.

Once you've determined the parental blood types you can see the possibilities for the children. (You can also work it backward if you know the child's blood type and one of the parent's to discover the other parent's blood type.) A parent with O type and a parent with A type blood can have O or A children. The only way to get AB blood is if (i) both parents are AB or (ii) one parent is A and the other is B or (iii) if one parent is AB and the other is A or B. When one parent is AB, then the child cannot be O. You cannot get a blood type that the parents do not have (i.e., a parent with type O blood and a parent with type B blood cannot have a child with type A blood).

While these general rules apply most of the time, the body is very complex and there are things like recessive anomalies that can occur. The best way to know anything for sure is to get some answers from a qualified medical professional.

People with Rh+ can pass on Rh+ or Rh-.
People with Rh- can only pass on Rh-.

Two people with Rh- can only have a child with Rh-. But two Rh+ people or, a Rh+ and a Rh- person, can have Rh+ or Rh- children. cindyt November 2, 2007

Can an O+ Father and an O+ Mother have an O- child?

A person only has type O blood if they got one O from each parent. If you get an O from one parent and a B from the other, you'll have type B blood. So an O parent and a B parent with B kids will have received one O and one B, making them have type B.

Negative Rh works like type O, so that the only way to have negative blood type is to receive the negative gene from both parents.

This means that even though your blood type looks like O+, what you actually got from your parents (and have the ability to pass to your kids) is OO+-. That is, a positive blood type can actually pass on a positive or negative blood type. A negative blood type, however, only can pass on negative.

So, someone with a B+ blood type can pass on B or O blood that is positive or negative. Dayton July 9, 2007

Hi eyes, You're right to ask &mdash it's not possible. If you have type O blood, the only possibilities for your child are O, A, or B, depending on the blood type of the father. eyes July 8, 2007

If I have an O blood type and my baby has an AB blood type does that mean the dad is AB also or is that even possible? Discussions on this page are currently closed.

Click here to order our latest book, A Handy Guide to Ancestry and Relationship DNA Tests

If my blood group is A positive, does that mean one of my parents would have to be the same?

- A curious adult from Alaska

No it doesn’t. Neither of your parents has to have the same blood type as you.

For example if one of your parents was AB+ and the other was O+, they could only have A and B kids. In other words, most likely none of their kids would share either parent’s blood type.

And that’s just one of many possibilities. There are lots of other possible combinations where two parents without blood type A can have a child with one. Here they are:

Now as to the positive part, that adds even more possibilities. Here is a table that I think goes through all the possible combinations where an A+ person would have a different blood type from his or her parents:

So there you have it. At least ten different combinations of parents without an A+ blood type can give an A+ blood type.

Before moving on, it is probably important to mention that there may be rare exceptions where an A+ child can come from parents with a different combination than one of these. Have a look through our previous answers on blood type to see how this might happen.

What I thought I’d do for the rest of the answer is focus on why these combinations can all give an A+ blood type. As you’ll see it has to do with two different genes and the different versions they come in.

Alphabet Soup: How A, B, and O are Different

First let’s go over a little bit about what it means to be A positive.

Blood cells naturally have lots of different sugars on their surfaces. The sugars that doctors look at to determine one part of your blood group come in three flavors – “A,” “B,” or “O.”

As you might have guessed, the A flavor makes the A sugar, and the B one makes the B sugar. It turns out that the O flavor doesn’t make any sugar.

Your blood type is determined by which combination of sugars you have. And this is determined by the genes you get from your parents.

Two Copies of Each Gene, One from Each Parent

DNA is a set of instructions for making and running a living thing. So your DNA is the set of instructions for making and running you.

A lot of these instructions are found in long stretches of DNA called genes. Each gene has the instructions for one small part of you.

One of these genes goes by the name ABO. It comes in three flavors, or “alleles” —A, B, and O. Your blood type is determined by the combination of alleles of this gene you get from your parents.

When you inherit a gene, you usually get two copies, one from your female biological parent and one from your male one. What this means for the ABO gene is that you can only have two of the three alleles of the ABO gene. The following chart shows you the different combinations that are possible:

Now here’s the part that’s a little complicated. When we talk about someone’s blood type, we care less about the gene combinations, and more about what they’re able to make. For example, someone that’s “AO” will be type A, because the O flavor of the gene makes no sugar. This person only has the A sugar.

Here are the blood types associated with each of the combinations of alleles:

As you can see, even though there are 6 different allele combinations, there are only 4 different blood types.

Now we have everything we need in order to explain how two parents without an A blood type might have a child with the A blood type. Here is an example of one of the ways we talked about in the first section:

In this example, your female biological parent is AB and your male one is O. Remember we only get one of one parent’s two copies and one of the other parent’s.

In this case, one gave you an “A” and the other gave you an “O,” so you’d be “AO.” This means you are the A blood type.

(I thought it would be important to mention that not every family looks like the family in this example – you may have two dads or two moms, who had you with the help of a donor. However, you would get your blood type from your female biological parent and your male biological parent.)

Another Gene Determines Positive/Negative

So now I know what you’re thinking – you’re A positive, so what does the “positive” part mean? It turns out there’s another important molecule on blood cells called the Rh protein.

You either have the Rh protein or you don’t. If you have it, you’re positive, and if you don’t, you’re negative. If you’re interested in knowing more about the Rh protein, you can visit one of our previous Ask a Geneticist answers.

As with the ABO sugars, one gene controls your Rh type. This gene comes in either a “working” form – meaning it makes Rh protein – or a form that makes no protein at all.

For you to be A positive, you must have inherited at least one working copy of the Rh gene from one of your parents. However, we don’t know for sure if one or both of your parents is Rh positive.

Instead of drawing out every combination of ABO and Rh, below is one example of how you might be A positive with neither of your parents being the same blood type as you:

Here, the female biological parent is AB negative and the male is O positive. The female has an A allele and a B allele for her ABO gene, and two negatives for her RH gene. The male has two O alleles of the ABO gene, and a positive allele and a negative allele of the RH gene.

In this case, the female happened to pass an A and a negative, and the male an O and a positive. So you are “AO +/-” genetically, meaning you have an A+ blood type.

We hope you enjoyed learning about blood types! If you’re still curious about blood types, including how and why the body doesn’t accept blood that doesn’t look like its own, check out this useful link.

Grandaunt and Granduncle

If you call your grandpa&aposs sister, your "great-aunt," you are not alone. But technically, this terminology is incorrect, according to experts. "Grand" refers to the generation above your parents (as in "grandparents"), though "great" implies an added generation beyond that. (Your "great-grandparents" are your grandparents&apos parents.) So really, your grandpa&aposs sister should be called your "grandaunt." But don&apost worry, we won&apost fault you if you keep referring to her by the more commonly used "great-aunt," and she probably won&apost either.

The Different Blood Types

There are eight different blood types:

A positive: This is one of the most common blood types (35.7% of the U.S. population has it). Someone with this type can give blood only to people who are A positive or AB positive.

A negative: Someone with this rare type (6.3% of the U.S. population) can give blood to anyone with A or AB blood type.

B positive: Someone with this rare type (8.5%) can give blood only to people who are B positive or AB positive.

B negative: Someone with this very rare type (1.5%) can give blood to anyone with B or AB blood type.

AB positive: People with this rare blood type (3.4%) can receive blood or plasma of any type. They’re known as universal recipients.

AB negative: This is the rarest blood type -- only 0.6% of the U.S. population has it. Someone with this blood type is known as a “universal plasma donor,” because anyone can receive this type of plasma.

O positive: This is one of the most common blood types (37.4%). Someone with this can give blood to anyone with a positive blood type.

O negative: Someone with this rare blood type (6.6%) can give blood to anyone with any blood type.

The four major blood groups are based on whether or not you have two specific antigens -- A and B. Doctors call this the ABO Blood Group System.

Group A has the A antigen and B antibody.

Group B has the B antigen and the A antibody.

Group AB has A and B antigens but neither A nor B antibodies.

Group O doesn’t have A or B antigens but has both A and B antibodies.

The third kind of antigen is called the Rh factor. You either have this antigen (meaning your blood type is “Rh+” or “positive”), or you don’t (meaning your blood type is “Rh-” or “negative”).

Why should I know my blood type?

Your blood type is something you&rsquore born with, and it&rsquos determined by your parents' genetics &mdash specifically, whether or not certain antigens are present in your body, according to the American Red Cross. Put simply, an antigen is a substance that prompts an immune response in the body it triggers your immune system to get into gear.

The main blood groups are based on the presence or absence of two antigens, A and B, on the surface of our red blood cells. People with neither A or B antigens have what's called Type O blood. The protein rhesus (also known as Rh) factor may also be present, known as positive, or absent, known as negative.

In the United States, O+ is the most common blood type, found in about 37% of the population, followed by A+ in around 36% of people, according to the Stanford School of Medicine Blood Center. AB- is the rarest, occurring in less than 1% of Americans. The Red Cross considers people with Type O- blood the &ldquouniversal blood donor,&rdquo because it can be used in emergency blood transfusions for any other blood type.

But do you really need to know your blood type? For most people, it isn&rsquot actually very important, says Stephanie Lee, M.D., president of the American Society of Hematology and associate director of the Clinical Research Division at the Fred Hutchinson Cancer Research Center in Seattle. "I think it's good in general to know about your health, but specifically, the two areas where [blood type] comes up would be transfusion or in pregnancy,&rdquo says Dr. Lee, who is also a professor at the University of Washington.

She explains that medical teams don't rely on you sharing your blood type before any major operation or blood transfusion they'll test your blood type beforehand. Pregnant women, in particular, routinely undergo blood-type tests to determine their Rh factor, and whether it is compatible with their baby. If a new mom has Rh-negative blood and their baby is found to be developing Rh-positive blood types, it could cause a number of complications, including miscarriage, if it's not caught early during pregnancy. Doctors can often administer what's called a RhoGAM shot to offset any problems with Rh compatibility.

How to Determine Positive and Negative Blood Types

This article was medically reviewed by Mandolin S. Ziadie, MD. Dr. Ziadie is a board certified Pathologist in South Florida specializing in Anatomic and Clinical Pathology. She earned her medical degree from the University of Miami School of Medicine in 2004 and completed her fellowship in Pediatric Pathology at Children’s Medical Center in 2010.

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Experts say that knowing your blood type is important, especially if you have frequent blood transfusions or you are trying to become pregnant. [1] X Trustworthy Source Red Cross Blood Donation Services Website run by the Red Cross Organization providing information about how and where to donate blood safely Go to source The ABO blood system labels blood types with the letters A, B, AB, and O. Your blood also has a Rhesus or Rh factor, which can be either negative or positive. You inherit your blood type and Rh factor from your parents. [2] X Trustworthy Source Mayo Clinic Educational website from one of the world's leading hospitals Go to source Studies show that to determine your Rh factor, you can find out your parents’ Rh factors for information or take a blood typing test at your physician’s office. [3] X Trustworthy Source Mayo Clinic Educational website from one of the world's leading hospitals Go to source

Are Sperm Donors Really Anonymous Anymore?

When Donor 3066 signed up with the California Cryobank, he offered some basic information about himself on a piece of paper: that he had a BA in theater that his mother was a nurse and his father was in the Baseball Hall of Fame that his birthday was Sept. 18, 1968. He made it clear that he didn’t want to be found by signing a waiver of anonymity.

The sperm bank protected his anonymity, just as it promised. But that did not mean he couldn’t be found. In an age of sophisticated genetic testing, the concept of anonymity is rapidly fading. With some clever sleuthing—tests that can track down ancestral origins, donor numbers, and bits of biographical information—parents and offspring can find out the donors. “With DNA testing and Google, there’s no such thing as anonymity anymore,” says Wendy Kramer, the founder of the Donor Sibling Registry. “Donors are choosing anonymity because they’re not educated. If they were properly educated on the consequences, then many would choose not to donate.”

Donor 3066 was being sought out by Michelle Jorgenson, a 39-year-old waitress from Sacramento, Calif., whose daughter, Cheyenne, was born in 1998. * When her daughter turned 5, Jorgenson joined the Donor Sibling Registry and began searching for other mothers and donor offspring who used Donor 3066. She was concerned because her daughter was sensitive to sounds and walked on her toes, and she wanted to know if other half-siblings were displaying similar behavior. Through the registry, she met a number of other mothers and half-siblings. She discovered that two had autism and two others showed similar signs of sensory disorder. Over the years, the group, which grew to 13 families, formed a bond around this anonymous man who was their biological link. They had unions and reunions and exchanged holiday cards, but none of this socializing answered any of Michelle’s questions about the donor’s identity. Because he signed a waiver, the California Cryobank would not release his identity. And because genetic testing is not part of their protocol or an FDA requirement, they could not offer any clues to his genetic history that might have caused these traits.

Jorgenson began talking to Wendy Kramer, the founder of the Donor Sibling Registry. Kramer suggested that she try to find her donor through an ancestry company such as Family Tree DNA, which helps people trace their ancestral heritage through cheek-swab cell scrapings. Her son had recently found his sperm donor this way. Because we get half of our DNA from our mothers and half from our fathers, almost all DNA gets shuffled and remixed every generation, making it impossible to trace what comes from whom. There are, however, two bits of DNA that are more pure and therefore easier to read. Mitochondrial DNA is located in the cytoplasm of the cell and is passed from a mother to their children, without recombining with anything else, but only the daughters pass it on to the next generation. * The other, the Y chromosome, passes directly from father to son. Just like a condensed computer file, scientists unzip the cells to obtain the DNA, which tells a story about a person’s ancestors and their migration roots and can lead to discoveries about personal identity and family history.

Jorgenson began her search by approaching a mother in her group with a son named Joshua and suggested he do a cheek swab so she could explore his paternal roots through a Y chromosome test. The mother agreed. Through the test, Michelle learned about some of Joshua’s genetic markers. A few weeks of searching on the Family Tree DNA Web site using these markers led to two families with matching DNA. Through one of the families, she met a woman who mentioned that she found the obit of a relative who was a former baseball manager, and three children were listed. Michelle suspected that this might be her donor’s father, so she looked up the phone number of his listed son. When Michelle called the number, the deceased man’s son answered the phone. She began to ask him questions: Was your father in the Baseball Hall of Fame? Were you born in Illinois? Did you ever donate sperm? When the man said yes, she asked him if his birthday was Sept. 18, 1968. When he answered yes, she burst into tears. “You’re the biological father of my daughter,” she said. He was shocked but agreed to talk to Cheyenne on the phone—and eventually allowed the two to come visit him in Los Angeles.

“I e-mailed the group when I found him and said I thought you would want to know,” she said. “Once they found out, everyone wanted to know who he was, and now he knows about all the kids. I talk to him a few times a year, but I’m the only mom who he’s agreed to talk to, and we’re the only family he’s met.”

Stories like Jorgenson’s are profound on several levels. Sperm banks are not bound by the FDA to do genetic testing of donors, but if they were, these new tests could offer a way for donor offspring to learn not only about their ancestry but about origins of specific genetic traits that could be linked to disease.

They also challenge the long-cherished idea of donor privacy. Most sperm banks now offer identity-release sperm, which means that donors have agreed to let their offspring contact their donor when they turn 18. But the great majority of donors still prefer anonymity, and profits hinge on ensuring it. College students are lured by the promise of easy money for doing what they would do for free. Few banks advertise—or even counsel their donors—that one day this easy money could result in dozens of children who might be curious about their genetics and ancestral routes, and a genetic family that could rival the size of one on Big Love.

“Donors are choosing anonymity because they’re not educated,” says Kramer. “If they were properly educated on the consequences, then many would choose not to donate.”

This new science is now forcing sperm banks to reconsider their policies and the education of their donors. “At this point, it’s hard to know how much it means, since the science is changing so quickly and we don’t know how many are actually looking for their donor,” says Alice Ruby, the director of the Sperm Bank of California, the only not-for-profit sperm bank in Berkeley, Calif. The Sperm Bank of California was the first sperm bank to spearhead the idea of the identity-release donor in 1983. Ruby says that the bank’s research of adolescent donor conceived children has shown that more than 80 percent of them are interested in finding their donors in the future. Ruby also said that only about 30 percent of families in their first class of identity-release donors have come looking for their donors. “We now tell donors that we’ll protect their identity, but that we cannot promise that future medical or technological advances will not make it possible for someone to identify who they are,” she adds. *

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