DNA Testing To Identify a Birth Parent

Do you have an unknown birth father OR mother? Here’s what to do to use DNA testing to identify your unknown biological parent, or at least to learn more about that parent’s family tree.


If you have one known parent and one unknown parent, you may be able to use a pretty straightforward process to identify your unknown parent, or at least to learn more about that parent’s family. I’ll explain this process using a real scenario, with details changed for privacy reasons. But you can follow these same steps yourself, adapting them for your own situation.

DNA Testing to Find a Birth Father or Mother

I know a woman—let’s call her Lora—who is looking for her birth mother. Lora was raised by her biological father, but all she knows about her birth mother is that she was working with her father at a Ford Motor plant in Detroit 80 years ago when Lora was born. The circumstances were such that Lora’s mother was forced to give Lora to her father to raise.

Click to read this related article.

Click to read this related article.

Lora guesses that her birth mother is probably long since deceased, but she’d still like to know who she was. She decides to take an autosomal DNA test.

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Getting Started

Lora tests at AncestryDNA because its huge testing pool increases her chances of connecting with close DNA matches. Since she knows her birth father’s family well, she researches and creates an online family tree for him on Ancestry.com. On this tree, she identifies her birth mother only as “birth mother,” with a residence in Detroit 80 years ago. (Here are more tips on creating the best online tree for your DNA profile.)

She Gets Her DNA Test Results…

When Lora receives her DNA test results, she links them to her tree. Next, she goes to her DNA home page and selects the option to View All DNA Matches. Since this is an autosomal DNA test, her matches include relatives on both her mother’s side and her father’s side. She needs to separate these matches from each other.

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The easiest way to do this is to identify the matches on her father’s side (which she knows something about) and set them to one side. In anticipation of this, on the top of her match list, she clicks Groups > Create a Custom Group and creates a group called “Mom’s side.” She repeats this process to create a group called “Dad’s side.” She chooses different colors to identify each group.

Next, Lora looks for the closest possible DNA match she can recognize on her father’s side. Ideally, she would have her father, her father’s sibling, or her own sibling by that father also test at Ancestry. But she doesn’t have that option, so she scans down the list of usernames and photos for familiar names and faces. (If she doesn’t find a close match here, she’ll use the Search box to search for his surname and his mother’s maiden name in both the Match Name and Surname in Matches’ Trees boxes, as shown below. Lora can widen this search to include more of his ancestral surnames, too.)

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Lora identifies a close DNA match on her father’s side: a first cousin. She clicks on the box Add/Edit Groups next to that match’s username and adds him to the “Dad’s side” group.

Click to read this related article.

Click to read this related article.

Then, on that match’s profile page, she selects Shared Matches. This shows her all those who have tested at Ancestry who share DNA in common with both herself and this relative of her father. Lora goes down the Shared Match list, adding each one to the “Dad’s side” group by using the option to Add/Edit Groups to the right of each of her close matches (4th cousin range or closer). When she finishes, she returns to the main match page. All close matches remaining without the “Dad’s side” label are added to the group “Mom’s side.”

(Note: if Lora’s birth parents were genetically related, this process won’t work. She’s beginning with the assumption that they were not.)

Working with an Unknown Birth Parent’s DNA Matches

Now that Lora has separated her birth mother’s DNA matches from those belonging to her father, she can focus on the former. Under Groups, she selects the Group “Mom’s Side,” and she begins reviewing this match list.

It is possible Lora will see a very close relative, such as the birth mom herself or a half-sibling, which Ancestry can identify by the genetic distance between them. But it is more likely her closest matches will be within the range of first to fourth cousins, which turns out to be the case. Only a few of them have trees posted and only a couple of them respond to messages she sends. (Here’s how to make your first conversation with DNA matches go better.) She feels discouraged and takes a break from the search for a few months.

But not forever. And it’s a good thing she comes back to it, because meanwhile, another important DNA match has popped up….