DNA tests for family history, what they can and can't tell you

A consumer DNA test can help with family history in two ways: it gives you an ethnicity estimate, and it connects you with relatives who have also tested. The matches are the more useful part for research, because they can confirm family lines and break through brick walls. The ethnicity estimate is a rough guess that changes between companies and over time. And no test can tell you names, places or stories; for those you still need records and your family.

The three kinds of DNA tests

Autosomal DNA is what most popular tests (AncestryDNA, MyHeritage DNA, 23andMe and FamilyTreeDNA's Family Finder) look at. You inherit it from both parents, and it's used for ethnicity estimates and for finding relatives on all your family lines. It's most reliable for relatives within about five or six generations.

Y-DNA passes from father to son almost unchanged, so it follows a single line: your father's father's father, and so on. Only people with a Y chromosome can take it, but a woman can ask her father, brother or a paternal male cousin to test. It's useful for surname studies.

Mitochondrial DNA (mtDNA) passes from mother to child, following your mother's mother's mother. Anyone can take it. It reaches very far back, but it's usually less useful for recent genealogy.

For most families starting out, an autosomal test is the right choice.

What the ethnicity estimate really means

Your ethnicity estimate compares your DNA with reference groups of people from different regions. It's an estimate, not a fact:

• Different companies give different results, because they use different reference groups.
• Results change when companies update their methods.
• Regions are broad. "Indigenous Americas—Mexico" or "Spain" won't tell you a town.
• It doesn't follow borders or culture. Many Mexican families see a mix of Indigenous American, European and African ancestry, reflecting centuries of history in their own family.

Treat it as an interesting picture, not a research answer.

Using your DNA matches

Your match list is where the research value is. The company shows people who share DNA with you and estimates how closely related you are, from parents and siblings to fourth cousins and beyond.

To use your matches well:

1. Build at least a basic family tree and link your DNA to it. Many matches will only make sense with a tree.
2. Start with close matches whose relationship you already know, like a known first cousin. They tell you which side of the family other shared matches come from.
3. Use shared matches to group people by family line.
4. Message matches politely. Say who you are, what family line you're researching and what you know. Many people test and never log in, so don't be discouraged by silence.
5. Confirm with records. DNA tells you that you're related, not exactly how. Combine it with records to identify the common ancestor.

Which test to choose

• AncestryDNA has the largest database of testers, which means the most matches, and works well with Ancestry family trees.
• MyHeritage DNA has many testers in Europe and Latin America, and good tools for matches.
• 23andMe also offers health reports, if those interest you.
• FamilyTreeDNA is the main option for Y-DNA and mtDNA tests.

Some sites let you upload results from another company's test, which can get you more matches without testing again. Policies change, so check each site.

Privacy and surprises: think before you test

• Read the privacy policy. Check who can see your results, whether your data may be used for research, and whether law enforcement can search the database. Many companies let you opt in or out.
• Companies can change hands. In 2025, 23andMe went through bankruptcy and was sold, which made many people rethink where their DNA data lives. You can usually download and delete your data.
• DNA is shared. Your test also reveals things about your relatives, who didn't choose to test.
• Be ready for surprises. DNA sometimes reveals unknown siblings, adoptions or a different biological parent. These discoveries can be hard. Think about how you would handle one before you test, and be gentle if you discover something that affects others.

DNA and the family's stories

DNA can tell you that you descend from someone, but not who they were. The names, hometowns and stories still come from records and from the people who remember. Talk to your oldest relatives alongside any test; our beginner's guide to family history research explains how, and Dalia can hold those conversations for you by voice, in English or Spanish.

Frequently asked questions

Which DNA test is best for genealogy?

For most people, an autosomal test from a company with a large database is best, because more testers means more relative matches. AncestryDNA has the largest database; MyHeritage is strong in Europe and Latin America. For a single paternal or maternal line, FamilyTreeDNA offers Y-DNA and mtDNA tests.

How accurate are DNA ethnicity estimates?

They're broad estimates, not precise facts. Results vary between companies and change as companies update their reference data. They're reasonably reliable at the continental level but much less precise for specific countries or regions.

Can a DNA test find my ancestors' hometown?

Not by itself. DNA can connect you with relatives who may know or have researched the hometown, and their family trees may name it. To find the actual town, you'll need records like baptisms, civil records or immigration papers.

Is it safe to take a DNA test?

It's a personal decision. Read the company's privacy policy, choose your settings for research use and law enforcement matching, and remember that companies can be sold. Your results also reveal information about relatives. You can usually download your data and request deletion.