While a child can have the very same blood kind as one of his/her parents, the doesn’t always happen that way. For example, parental with abdominal and O blood varieties can one of two people have children with blood kind A or blood form B. These two varieties are definitely different 보다 parents’ blood types! 

But 2 O parents, for example, will certainly pretty much constantly have O kids. They will complement both parents.

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As you can see, periodically kids’ blood species match and also sometimes castle don’t. There are specific chrischona2015.org “rules” that allowed me to acquire to this answer, which I breakdown for you below. However like any an excellent rules, there room exceptions. 

See the web links at the bottom ~ above this web page to previous answer that discuss some of this rule-breaker situations. Keep in mind though that they are very rare. Nearly all cases follow a collection of chrischona2015.org rules based upon how genes room passed under from parental to child. 

One Gene deserve to Lead come Four various Blood Types

Let’s start with DNA. DNA has actually the instructions because that making a life thing. So your DNA has actually instructions because that making you.


Each particular instruction for a small component of girlfriend is referred to as a gene. Together humans, us all have the very same 20,000 or for this reason genes. What provides us different are the different versions of these genes.

For example, we all have the blood type gene, ABO. What offers us different blood species is that this gene come in three different versions: A, B, and O. 

In a an easy world, the 3 versions would give three blood species and a child would have one the the blood types of the parents. Yet we don’t live in a an easy world, now, execute we?

There’s one more thing we have to know about our genes- we have actually two copies of most of them. We obtain one copy from our mom and one from ours dad. Each of her parents have actually two duplicates of each of your genes, and they each pass one under to you.

Can you start to see exactly how this may complicate things?

Since we obtain these gene from our parents, it is common to share particular traits through our parents, like blood type. However like I said at the start, it is not constantly the case. 

Because we have two duplicates of the blood type gene and also there room three possible versions of this gene, there are six possible combinations. Officially complicated! castle are: 

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These are dubbed blood form genotypes. Castle are all of the possible combinations that the 2 gene version together.

Ok for this reason we have actually six combinations and also only 4 blood types. Lets see why the is.


Gene-Protein Relationship

I told friend there room all these different genes and also that they come in versions. However what specifically do castle do and also what is different around them?

Genes room the instructions for proteins. And different gene execution make various versions the a protein. 

So the A variation of the ABO genes renders the “A” variation of a protein, the B variation a B variation of a protein and also importantly, because that our discussion, the O variation doesn’t make either.

Your blood form is determined by which of these proteins you in reality make. This is why there room four various blood types.

Remember our 6 genetic combinations, or genotypes? Well, because O means no protein, below is exactly how they failure into four blood types, or phenotypes: 

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So AO is A blood kind because it only makes the A protein version. Exact same thing with BO except it is blood kind B because it just makes the B version. The O contributes nothing. Except, perhaps, in the next generation. 

How to figure Out a Child’s possible Blood Type

Ok so currently we have whatever we must predict what blood form a boy will likely have offered two parents. All we require to understand are the parents’ blood genotypes.

Using a Punnett square is a good way to figure out a child’s feasible blood varieties based ~ above the parents’ blood types. A Punnett square is just a diagram that helps come organize every one of the genes to number out the likelihood because that a certain mix of genes. 

First, put the 2 ABO gene versions indigenous one parent follow me the height like this: 

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Here us made dad AA, i m sorry is his genotype, or his 2 gene execution together. He could additionally be AO and still have an A blood type, favor we experienced above.

To save track of things, the A blood kind will it is in shaded blue.

Then, let’s say mom is AA too. We put her genotype in these two squares (marked v the arrow). 

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If both parents are AA blood type, then that’s a rather straightforward Punnett square and also the child can only have actually the exact same blood kind as mom and dad. Let’s work-related through the Punnett square to view how.

For this to work, psychic that we only acquire one copy that a gene from mom and also one indigenous dad. So, because that example, dad will pass either his first A or his 2nd A but not both. When this isn’t very important in this example, because the two genes space the same version, you’ll see exactly how it is in later on examples!

So let’s do box 1 first. Over box 1 is dad’s first A and also to the left is mom’s very first A. We integrate them to obtain the first possible combination. 

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If you proceed doing the exact same in box 2-4, you acquire this finished pedigree. 

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As you have the right to see by all of the blue boxes, the child’s only feasible blood type mix is AA, as with the parents. For this reason 100% that their children will be AA.

Now let’s watch what we gain with two AO parents. Just like before, we are starting with 2 parents with A blood type. 

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But now, the Punnett square looks different!

Even despite both parental still have actually blood form A, Dad have the right to pass on either his A or his O gene version. Mother can additionally either pass on she A or she O.

Because of this, you deserve to see that there’s 1 in 4 or 25% opportunity for a boy to have OO, or blood kind O.

How did I gain a 1 in 4 chance? allow me display you!

The child can have 4 feasible genotypes the I’ve shaded here in gray for this reason you deserve to see what I’m talking about. 

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Yes, AO is over there twice, but they still count as different possibilities.

Out of those 4, three combinations offer blood form A, i’ve shaded those in lighter blue below. 

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One combination, OO, offers blood form O.

So yes a 1 the end of 4, or 25% chance, that the boy will have blood type O and 3 the end of 4, or 75% possibility that the boy will have blood form A.

This example shows the prominence of knowing the parents’ genotypes to number out a child’s possible blood type. Just knowing “type A” isn’t enough information. You require to recognize the genotype, one of two people AA or AO.

Let’s shot one more!

What if the parents were ab and O blood type? You have the right to start by put the genotypes that the two parents in the correct squares. 

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Here the abdominal blood kind is displayed in purple.

Now we integrate the blood form letters choose we did before.

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Now, you can see a case where the child’s possible blood kind combos room unlike either of the parents. The kid of an abdominal dad and a OO mom might either it is in AO (blood kind A) or BO (blood form B).

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You could do a Punnett square for every possible mix of parent blood types. Or, you can look at this ahead question and scroll to the chart at the bottom.

Hopefully you deserve to see how it’s virtually impossible to say that in general, kids have the same blood kind as among the parents! yet using chrischona2015.org knowledge and also Punnett squares, us can figure out the possibilities because that a children blood form based top top the parents’ blood types.