Can a DNA Test Help Me Find Relatives and Lost Family Members?
Updated on May 8, 2025
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Can a DNA Test Help Me Find Relatives and Lost Family Members?
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Key Takeaways

  • Big databases matter: More test‑takers mean closer matches are likelier to show up.
  • Centimorgans (cM) translate to closeness: Think of cM as the DNA “yard‑stick.” More shared cM usually signals a closer relative.
  • Upload once, search everywhere: Export your raw file to GEDmatch and other portals so you don’t miss cousins who used a different company.
  • Privacy sits in your hands: Most sites let you opt in—or out—of law‑enforcement searches with a single toggle.
  • Patience wins: No strong lead today? New kits arrive daily. Set alerts and check back each month.

DNA Relative Matching

It’s exciting—and a little scary—to open a match list for the first time. You’ll see numbers, acronyms, and strangers who might be family. Let’s slow down and translate the basics.

Your kit compares autosomal DNA, the 22 chromosome pairs you inherit from both parents. When two people share long, identical stretches, the software flags those pieces as identical by descent—evidence you both got that DNA from a recent common ancestor.

Scientists measure each shared stretch in centimorgans (cM). A centimorgan is a unit of genetic distance, not a physical length. The higher the total cM between two kits, the closer the likely relationship.

Likely RelationshipTypical Shared cMHow It Looks in the Results
Parent / Child~3,500Dozens of very long segments across many chromosomes
Grandparent~1,700Long segments on half the chromosomes
First Cousin~850Several segments over 50 cM
Second Cousin~230Mix of long and short pieces

Why Database Size Counts

Imagine fishing with a net the size of a bathtub versus the size of a football field. AncestryDNA has more than twenty million profiles, so your “net” is huge. Smaller sites—though still valuable—may miss that one cousin who holds your missing surname. Uploading your raw data widens the net without buying a second kit.

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Best DNA Kit

Don't miss out on the opportunity to learn more about yourself. Read our best DNA test page to find the best one for you.

Choose the Best Test

Picking a company can feel like betting on the right horse. Here’s a quick, no‑jargon guide:

  • AncestryDNA – Biggest match list, excellent family‑tree tools. Lacks a chromosome browser.
  • 23andMe – Adds health reports. Includes a browser to see exactly where segments overlap.
  • MyHeritage – Smaller U.S. presence but strong in Europe and Latin America. Handy “cM Explainer” guesses relationships for you.
  • FamilyTreeDNA – Offers Y‑DNA and mtDNA for deep paternal or maternal lines. Smaller autosomal pool.
  • GEDmatch (upload) – A free, third‑party site that lets kits from all brands compare in one place.

Reader tip: Buy one main kit—often Ancestry for its size—then upload the raw file to every free portal allowed. That single step can double your cousin list overnight.

Step‑by‑Step Search Plan

Searching without a map leads to overwhelm. Follow these four checkpoints.

1. Sort Your Matches

Start with the person who shares the most cM. If a known relative (say, Mom) also tested, label every cousin who overlaps with her as “Maternal.” Most sites offer a Shared Matches button to speed this up.

2. Build a Mirror Tree

Open a blank family‑tree program. For each top cousin, add their parents and grandparents using public obituaries, census pages, or social‑media hints. You’ll soon spot repeat surnames or hometowns that point toward a common branch.

3. Triangulate Segments

Upload your best matches to GEDmatch and run the Triangulation tool. It highlights chromosome spots you share with two or more cousins at once. When that happens, all of you inherited that exact DNA block from the same ancestor—your investigation just narrowed to one lineage.

4. Confirm With Records

Once a likely ancestor appears, chase birth certificates, marriage licenses, and newspaper clippings. A polite message—“Hi, I think we share Great‑Grandpa James”—often unlocks family stories no database can hold.

Privacy and Feelings Matter

Finding family can be joyful and jarring in the same breath. It’s normal to feel anxious before clicking “View Matches.”

  • Law‑enforcement access: Most companies require your explicit opt‑in before police can search your profile, and they still need a warrant. Check your settings.
  • Unexpected parentage: Roughly one in fifty testers discovers that a parent or grandparent isn’t biologically related. If that possibility worries you, talk it through with a counselor first.
  • Data deletion: All major kits let you wipe your DNA file and destroy the sample. Keep the power to reverse course.

Remember: DNA tells a genetic story, not the whole story. You decide how, when, and with whom to share each chapter.

Common Roadblocks—and Work‑arounds

  • Endogamy or cousin marriage: Groups with tight historical communities (Acadians, Ashkenazi Jews) share extra DNA. Focus on segments longer than 15 cM and ignore the tiny ones that create noise.
  • Small databases for your heritage: If you have recent African or Asian roots, matches may be sparse. Upload to sites with stronger coverage in those regions and invite relatives to test.
  • No close matches yet: Databases grow daily. Set e‑mail alerts for new high‑cM hits and re‑check monthly. Even a distant third cousin can break a case once fresh records appear online.

Next Steps

  1. Order a kit that aligns with your budget and region of interest. Watch for holiday sales.
  2. Plan your uploads—save the raw file once results arrive.
  3. Set emotional expectations with loved ones before sharing discoveries.
  4. Find community—forums like DNAAdoption or SearchAngels pair newcomers with seasoned volunteers.

Finding family is rarely instant, but each clue builds on the last. With steady work—plus empathy for yourself and others—you can turn cold paperwork into warm connections.

The Best DNA Test to Find Lost Relatives

1. 23andMe - Our Top Pick

Can a DNA Test Help Me Find Relatives and Lost Family Members? 3

23andMe DNA Test Pros

  • Comprehensive ancestry test – Track your DNA ancestry from over 1,500 different regions.
  • DNA matches – Helps you find lost and distant family members.
  • Understand your genetic traits – 23andMe tests your DNA swab for genetic markers associated with various traits, including freckles, hair, taste, and more.
  • No hidden fees – Once you pay for the test, you get full access to their services.

23andMe DNA Test Cons

  • No cross-platform support – You can't upload raw genetic data from competitors.

23andMe does all three tests: mtDNA, Y-DNA, and autosomal. Combined with a massive DNA database, it's one of the most accurate tests for ancestry. 

Here’s our 23andMe review if you want to learn more.

2. AncestryDNA

Can a DNA Test Help Me Find Relatives and Lost Family Members? 4

Ancestry DNA Test Pros

  • Easy to take – Requires a small saliva swab for a DNA sample.
  • Precise ethnicity estimates Get a detailed geographic breakdown of your ethnicity.
  • Migration patterns Discover the migratory routes your ancestors may have taken.
  • Find lost relatives – Matches your DNA with distant relatives you may not know.
  • Raw DNA data – Downloadable results that you can use on other DNA testing companies.

Ancestry DNA Test Cons

  • Limited access – To build a family tree, you must pay monthly fees to access public records and other users' family trees.
  • Doesn't estimate your racial group –AncestryDNA only performs genetic matches based on geography, not racial profile (e.g., Asian, American, and European).

Additional services can get expensive. However, its massive database makes it one of the most trusted DNA tests, so many think it earns its price tag. You can learn more about AncestryDNA here

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Updated on May 8, 2025
Cristine Santander
Cristine Santander
Content Contributor
Cristine Santander is a content writer for KnowYourDNA. She has a B.S. in Psychology and enjoys writing about health and wellness.