How Much DNA Do I Share With My Child?

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If you have done an autosomal DNA test, you might be wondering what the average number of centimorgans (cMs) a parent will share with their child.

Your child will share very close to 50% of their DNA with you, which equals around 3400 cMs.

Keep in mind that your child will not match your DNA at 100%.  DNA is passed down randomly in a process called random recombination.  50% of your DNA will not be passed down to your child.  The same goes for your child’s other parent.

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Is it possible for a child to have more DNA from one parent than the other?

No, your child will inherit 50% from the mother, and 50% from the father.  There is no way that someone has more DNA from one parent.

Ethnicity results and your parent’s DNA

It is also possible for your parents to have an ethnicity show up in their DNA that does not show up in yours.  How can this be?

When you inherit your DNA, there is 50% that does not get inherited.  So just because you don’t show any Irish ancestry, doesn’t mean that your mother or father won’t (if they test).  There is always the possibility that the Irish ancestry was in the half of their DNA that you didn’t get.

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It is also possible for you to have an ethnicity in your DNA results that does not show up in your parent’s DNA.  This might sound crazy – how is it possible to inherit DNA that neither of your parents have?

You are 100% correct. You can’t inherit something that you parents don’t have.  It is possible, however, that your father had a trace amount of Native American ancestry and your mother had some, too.  Together, the trace amount could add up to over 1-2%, which would show up on your test.

Have you found any surprises, either with amount of shared DNA or ethnicity, when testing yourself and/or your parents?  I’d love to hear about it!

If you want a more complete, in-depth guide about how to understand and use your DNA results to find family and build your tree, click HERE to learn about my ebook guide to your DNA results.