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What can a DNA Test With My Mom Tell Me?

If you have already done a genealogical DNA test, you might be wondering if there is any point in having your mom or dad take one, too.   If you want to know what you can learn from testing mom or dad, you have come to the right place. 

It turns out, you can unlock a wealth of information about your family’s history by having your parents do a DNA test!

What can a DNA Test With My Mom Tell Me_

You share 50% of your DNA with each of your parents.  This means that both your mother and father has a huge portion of DNA that they don’t share with you.

Does that sound crazy? No worries.  In this post, I will explain to you:

  • The benefits of testing your parents – even if one or more of your siblings has tested
  • Why your parents could show an ethnicity that you don’t have
  • How your parents will have different DNA matches than you

Benefits of having parents do a DNA test

There are several benefits to have your parents take a genetic DNA test, like the one offered from Ancestry DNA, Family Tree DNA, or 23 and Me:

  • You can discover new ethnicity that was not inherited by you or any siblings
  • Find additional living relatives
  • Acquire valuable information that can help trace your family tree

If you are unable to have one or both of your parents take a DNA test, you can also ask one of their siblings if they would be willing to test.  Your parents’ siblings will share common ancestry with you, and their DNA will offer similar benefits for tracing family history, ethnicity, and finding matches.

Even if one or more of your siblings has done a DNA test, there are still concrete benefits in testing your parents.  Each child inherits 50% of their DNA from their parents, but it will never be the exact same 50% that your sibling inherited. 

Even if a couple has several children, there will always be a random amount of DNA from each parent that did not get passed down.

Click here to buy the Understand Your DNA Results Ebook

Find new ethnicity by having your parents do a DNA test

Your personal ethnicity estimate is only a snapshot of a portion of your family’s true ethnic background.  You have inherited DNA from only some of your more distant ancestors. 

As you already know, you did not inherit 50% of each of your parents’ DNA.  The same is true for each generation, meaning that over the course of a few generations, some DNA is completely lost.

Cool fact: Did you know that it is statistically possible to share absolutely no DNA with a great-great grandparent?   With each subsequent generation, there is a higher probability of sharing no DNA with the original ancestor.

In the graphic below, you can see my own personal DNA ethnicity estimate compared with those of my mother, father, and paternal grandmother.  If you look closely, you can see how there was one ethnicity lost between my father and I, and there are two ethnicities that I did not inherit from my mother.

Ethnicity: patterns of inheritence

As you can see, there is much to learn by testing parents, and even grandparents if they are able and willing.

Testing your parents DNA can help you find more living relatives

The DNA that you don’t inherit from each of your parents contains valuable information.  Those DNA segments that got left behind will match relatives that you don’t match. 

You and your parents will share all close relatives, and those cousins who fall into the 1st-2nd cousin range.

By the time you get to the 3rd cousin level, however, it is possible that your parents will have cousin matches that you don’t have.  Even more likely, however, is that the 3rd cousins of your parents will show up on your list, but you will share a much smaller amount of DNA with them. 

They may be so far down on your list that you don’t even notice that they are there.

For example, we can look at one of my mother’s second cousins.  They are actually half-second cousins, since their great-grandfather remarried, and they share a different great-grandmother. 

The effect of this “half” relationship on their DNA means that they share 50% less than they would have shared had they been “full” second cousins.  Because of their “half” relationship, I share a very small amount of DNA with him, and he shows up far down on my 4th-6th cousins list. 

Without my mother’s test results, I may not have even looked closely at him.

By testing your parents, you will be able to spot those closer relatives and get to know them, if you are interested.  This leads me to the final reason that you should test your parents.

Your parents’ DNA matches can provide valuable genealogical information

Even if you aren’t interested in having a family-type relationship with your DNA matches, you might be surprised by what you can learn from them.  On Ancestry DNA, for example, many people have public family trees. 

The same is true on Family Tree DNA.   By using these family trees, there is a chance that you can use this information to build your family tree further back.  In addition, you can consider contacting some of these matches in order to see if they have documents, photographs or other records that can help you learn the most about your family.


I sincerely hope that this post has helped you learn how you can benefit from your parents doing an autosomal DNA test.  I have learned so much by testing multiple family members, especially my parents and grandmother.  I hope that the experience is just as positive for you.

If you have any questions about anything that I mentioned in this post, I would love to hear from you in the comments.

Thanks for stopping by!

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