Should a Male or Female Sibling Take a DNA Test

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If you are interested in DNA testing, and you are a female with male siblings, or a male with female siblings, you might be wondering which one of you should be the one to take a DNA test. 

Does it make any difference?  Will your results be the same? 

If you are full siblings, don’t you basically have the same DNA, anyway?  Is there a type of DNA test that is better for males to take? 

In this post, I’ll answer all of these questions for you. You are sure to learn something new.

Should a male or female sibling take a DNA test?

The short answer is that both siblings should take a DNA test, if possible. There are various types of DNA tests and the one that is right for you and your siblings will depend on what you would like to achieve with the results of the test.

The long answer is contained within this post – and if you read the whole thing, you’ll understand exactly why it is beneficial for both male and female siblings, and even all siblings, to take a DNA test.

It’s important to note that there are different types of DNA tests and some only work for males.  This article will explore more on that below.

We have different “types” of DNA in our bodies, and some tests only examine one particular kind.  What’s more, there is one type of DNA that males have that females don’t have, so it’s important to choose your DNA testing path carefully depending on exactly the type of information that you are looking for.

What are the types of DNA tests for ancestry?

There are three main types of DNA tests that people use to learn about their family history:

• Y DNA tests
• mtDNA tests
• autosomal (atDNA) tests (like the type offered at Ancestry DNA, 23 and Me, My Heritage, and Family Tree DNA)

See, it’s easy!  There are only three main types of tests.  Once you learn what each one does, and who can take them, you’ll know exactly whether you or your brother (or you and your sister) should both take a test, or whether only one of you needs to.

Below, I will give you a short explanation about each type of DNA test:

Who can take a Y DNA test?

Only males have Y DNA, and males can only pass Y DNA down to their male offspring.  This means that only males can take a Y DNA test, and this test can only provide information about the male line of the family.

If you are female and have a brother (or can test your father), you can learn about your family’s direct male line.  It’s true that this only covers a small percentage of total ancestry, but it can be interesting. 

Additionally, this information can use to verify your male ancestral line.  Y DNA tests go back many thousands of years into time because Y DNA changes very, very slowly – it’s passed down intact over centuries.

Who can take a mtDNA test?

mtDNA stands for “mitochondrial DNA”, and we all have it.  Both males and females have mtDNA that they inherited from their mother, and so both males and females can take a mtDNA test. 

With that said, some testing companies offer males the chance to take a mtDNA test and a Y DNA test at the same time, so if you have a brother (or you are a male) who is willing to test, this is ideal.  If you have the same mother, your mtDNA will be the same, and if you have the same father, his Y DNA will be the same as your father’s Y DNA.

It’s important know that mtDNA is passed down directly from mother to children, and so the mtDNA test will only reveal the direct maternal line (i.e. your mother’s mother’s mother’s mother’s mother’s mother’s ancestry) going back thousands of years.

mtDNA changes even more slowly than Y DNA.  Some companies, such as Family Tree DNA, also offer mtDNA matching (and Y DNA matching) where you can find people who match your mtDNA results, but since this type of DNA changes so slowly, it’s hard to know whether you share a common maternal ancestor 100 years ago or 1000 years ago.

Mitochondrial DNA is very interesting to learn about. Have you heard of the theory of “Mitochondrial Eve“, the most recent direct-line maternal ancestor shared between all humans alive on earth?

Of course, going back tens of thousands of years is not what most of us are looking for. This type of information is not very helpful for building a family tree, of course

The mtDNA and Y DNA tests will only reveal information about 2% of your family’s ancient ancestry, and this information has limited use for learning about your family’s more recent (300-500 years) heritage.

Who can take an autosomal (atDNA) test?

I’ve got good news for you.  Everyone has autosomal DNA, and therefore, everyone can take an autosomal DNA test and learn the same type of information.  Autosomal DNA is inherited from both the mother and father, which means that autosomal DNA test results can help anyone, whether they are male or female, learn about both sides of our family tree.

I’ll talk more about the how and the why below, but you should also know that parents don’t share 100% of their autosomal DNA with their children, and full siblings don’t share 100% of their autosomal DNA with each other. 

This means that if two siblings, or all siblings, take an autosomal DNA test, each test will reveal slightly different information about a family’s roots.

Autosomal DNA is contained within all of our numbered chromosomes, and as such, this some of this DNA is passed down to all of their offspring. Autosomal DNA tests are offered by many companies, but the most reputable and most experienced companies offering this type of testing are listed below. You can also order your test by clicking directly on one of the links.

Autosomal DNA tests can show information about your family’s recent ancestry going back a few hundred years to as far as a thousand, but usually no further than that.  Your autosomal DNA results can tell you where your family likely lived a hundred years ago, based on your ethnicity estimate and your DNA matches. 

If you’ve seen television advertisements or internet ads for DNA testing that include a pie chart or percentages of a particular ethnicity or region of the world, it’s most likely that these ads were for autosomal DNA tests.

Do siblings have the same DNA?

If you read the first part of this post about Y DNA and mtDNA tests, you probably understand that females don’t have Y DNA and males and female siblings with the same mother share the same mtDNA, so this section is going to address autosomal DNA. 

Two full siblings with the same mother and father don’t share all of the same autosomal DNA.  In fact, most full siblings share less than half of their autosomal DNA with each other.

Because any two full siblings won’t likely share even 50% of their DNA with each other, there is a wealth of information that can be learned from each sibling’s autosomal DNA results.  Full siblings can share as little as 33% of their DNA with each other – that’s a lot of missing information if only one sibling decides to do a test!

The DNA that siblings don’t share with each other can reveal more about the family’s cultural heritage and where some of your ancestors might have lived in the world, especially your more distant ones.  Additionally, two full siblings won’t have identical DNA match lists. 

There are DNA segments that each sibling has that the other doesn’t that will match genetic relatives, and information from these relatives can help build a more complete and accurate family tree.

I’m a very big fan of autosomal DNA testing (like, a huge fan), and I love it when I see siblings all do tests because it gives a much more complete picture of a family’s unique history than just one sibling doing a test.

Conclusion

I hope that this post helped you learn whether or not male and female siblings have the same DNA, whether or not they can both take DNA tests, and which sibling can take each type of DNA test. If you have any questions about something that you read in this post, I would love to hear from you in the discussion below.

Thanks for stopping by!

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