DNA Testing for Family History: Which Test Should You Take?

DNA testing has revolutionized genealogy. For $100, you can discover ethnic origins, find unknown relatives, and break through genealogical brick walls that would have been impossible to crack 20 years ago.

But DNA tests aren't all the same. Different companies test different things. Understanding what you're actually buying—and what the results mean—is essential.

This guide cuts through the marketing to show you exactly which test to take and how to use the results for family history research.

The Three Types of DNA Tests

DNA tests for genealogy fall into three categories. Each reveals different information.

1. Autosomal DNA (Most Common)

What it tests: All your DNA from all ancestors Tests: AncestryDNA, 23andMe, MyHeritage, FamilyTreeDNA, LivingDNA

What you get:

• Ethnicity estimate (what % Irish, Italian, African, etc.)
• Cousin matches (people who share DNA with you)
• Roughly 5-6 generations of ancestry information

Best for:

• Finding living relatives
• Confirming research
• Breaking through brick walls
• General ancestry exploration

Limitations:

• Only goes back 5-6 generations reliably
• Inheritance is random (siblings get different DNA from same ancestors)
• Can't determine specific ancestral lines beyond recent generations

Who should take it: Everyone interested in genealogy. This is the starting point.

2. Y-DNA (Males Only)

What it tests: Y chromosome (passed father to son unchanged for generations) Tests: FamilyTreeDNA

What you get:

• Direct paternal line ancestry (father's father's father...)
• Matches to other men in same paternal lineage
• Deep ancestral origins (thousands of years back)
• Surname connections

Best for:

• Tracking paternal surname line
• Confirming paternal ancestry beyond paper trail
• Ancient paternal origins

Limitations:

• Only males have Y chromosome
• Only shows one ancestral line (ignores 50%+ of ancestry)
• Fewer people have taken Y-DNA test (smaller database)

Who should take it: Men interested in paternal surname research. Women can ask male relatives (father, brother, uncle) to test.

3. Mitochondrial DNA (mtDNA) - Everyone Has It

What it tests: Mitochondrial DNA (passed mother to all children, but only daughters pass it on) Tests: FamilyTreeDNA

What you get:

• Direct maternal line ancestry (mother's mother's mother...)
• Ancient maternal origins
• Matches to others in same maternal lineage

Best for:

• Tracking direct maternal line deep into history
• Confirming maternal ancestry beyond paper trail

Limitations:

• Only shows one ancestral line
• Even smaller database than Y-DNA
• Less useful for recent genealogy (paper trail is usually sufficient)

Who should take it: Serious genealogists interested in deep maternal ancestry. Not essential for most people.

Company Comparison: Which Service?

AncestryDNA

Price: $79 (regular sales)

Database size: 20+ million (largest)

Strengths:

• Biggest database = most cousin matches
• Integration with Ancestry trees (see matches' family trees)
• Excellent tools for analyzing matches
• Best for US research

Weaknesses:

• No health reports
• No raw DNA download on some plans
• Subscription required for full tree access ($25-50/month)

Best for: Finding living relatives, US-based research, beginners

23andMe

Price: $99-$199

Database size: 12+ million

Strengths:

• Health reports included (higher tiers)
• Neanderthal ancestry (fun but not useful)
• Chromosome browser (see exact DNA segments shared)
• Good ethnicity estimates

Weaknesses:

• No family tree integration
• Worse genealogy tools than Ancestry
• Smaller database

Best for: Health + ancestry, international users, those interested in genetic health

MyHeritage DNA

Price: $79

Database size: 5+ million

Strengths:

• Strong international database (especially European)
• Free family tree software
• Matches to other databases (if you upload)
• Ethnicity estimate included

Weaknesses:

• Smaller US database
• Interface not as intuitive

Best for: Non-US ancestry, international research, European roots

FamilyTreeDNA

Price: $79-$359 (depending on test type)

Database size: 2+ million autosomal, largest Y-DNA and mtDNA databases

Strengths:

• Only company offering Y-DNA and mtDNA
• Advanced tools for serious genealogists
• Good for deep ancestry research

Weaknesses:

• Smallest autosomal database
• Interface dated
• Steeper learning curve

Best for: Serious genealogists, Y-DNA/mtDNA testing, paternal/maternal surname projects

My Recommendation

For most people:

1. Start with AncestryDNA (largest database, best tools)
2. Upload raw data to MyHeritage and FamilyTreeDNA (free, expands matches)
3. If you want health data, also take 23andMe

For serious genealogy:

• AncestryDNA (autosomal) + FamilyTreeDNA Y-DNA (if male) or ask male relative

For international ancestry:

• MyHeritage + 23andMe

Understanding Your Results

Ethnicity Estimates: Fun, Not Fact

Your results will show percentages:

• 45% British & Irish
• 30% Western European
• 15% Scandinavian
• 10% Nigerian

Important truths:

• These are estimates, not facts
• Each company gives different percentages
• Percentages change as databases improve
• Small percentages are often noise
• Can't pinpoint specific countries accurately

What ethnicity ACTUALLY tells you:

• Broad geographic origins
• General regional ancestry
• Confirmation of family stories (or surprises)

What it doesn't tell you:

• Exact countries or regions
• Specific ancestors' origins
• Your "true" percentage (it's an estimate)

Use ethnicity estimates as starting points for research, not definitive answers.

Cousin Matches: The Real Value

This is where DNA gets powerful for genealogy.

How matches work:

• Shared DNA measured in centimorgans (cM)
• More cM = closer relationship
• Companies predict relationship

Relationship ranges:

• 2000-3500 cM: Parent/child
• 1300-2300 cM: Full sibling
• 850-1350 cM: Half-sibling, grandparent, aunt/uncle
• 425-850 cM: 1st cousin
• 215-425 cM: 1st cousin once removed, half 1st cousin
• 100-215 cM: 2nd cousin
• 45-100 cM: 2nd-3rd cousin
• 20-45 cM: 3rd-4th cousin

Strategy for using matches:

1. Start with closest matches (highest cM)
2. Check if they have family trees
3. Look for common surnames or locations
4. Build out their trees (mirror trees) to find connection
5. Contact them (politely) to share research
6. Use grouping tools (Leeds Method) to identify ancestral lines

Breaking Through Brick Walls with DNA

Real-world applications:

Problem: Unknown Parent or Grandparent

DNA can identify biological family:

• Test yourself
• Closest matches are likely within 2-3 generations
• Build their trees
• Look for common ancestor
• Triangulate between multiple matches

Problem: Adoption

DNA is revolutionary for adoptees:

• Matches reveal biological family
• Multiple matches narrow down specific family line
• Search angels and specialists can help interpret results

Problem: Records Don't Exist

When paper trail ends, DNA continues:

• Matches who descend from same ancestor prove connection
• Multiple matches confirming same lineage provide evidence
• Can bypass missing records

Problem: Multiple Possibilities

DNA confirms which theory is correct:

• Test with predicted relatives
• Shared DNA confirms relationship
• No shared DNA rules out connection

Common Pitfalls

1. NPE (Not Parent Expected) DNA sometimes reveals:

• Adoptions
• Infidelity
• Unknown parentage

Be prepared for family secrets. Results can't be unseen.

2. Half-relationships Siblings who share only one parent show up differently than expected. Causes confusion if unknown.

3. Endogamy Some populations (Jewish, Mennonite, isolated communities) show inflated relationships due to cousin marriage generations back.

4. No Matches Very rare ethnicity or small family might have few matches. Not a failure—database is constantly growing.

5. Too Many Matches Overwhelming number of 4th-6th cousins. Focus on closest matches first.

Privacy Concerns

DNA testing raises legitimate privacy questions:

What companies know:

• Your genetic data
• Relationship to other testers
• Health markers (some tests)

What they might do:

• Share with law enforcement (with warrant—has happened)
• Sell anonymized data to researchers (most do this)
• Change terms of service

Protecting privacy:

• Read privacy policies carefully
• Opt out of research sharing if uncomfortable
• Use pseudonym instead of real name
• Don't connect to family tree publicly

Law enforcement:

• Has used genealogy databases to solve cold cases (Golden State Killer)
• Requires public databases (GEDmatch) or warrants
• Generally considered good use, but privacy concerns valid

Decide where you stand on this before testing.

Taking Action

This month:

1. Choose test (AncestryDNA for most people)
2. Order and register kit
3. Follow instructions (don't eat/drink 30 min before)
4. Mail back (don't forget this step!)
5. Wait 4-8 weeks for results

When results arrive:

6. Review ethnicity (interesting but not critical)
7. Sort matches by relationship closeness
8. Review closest matches' trees
9. Look for common surnames/places
10. Message matches with shared interests

Ongoing:

11. Check matches regularly (database grows constantly)
12. Build out family tree to compare with matches
13. Join DNA groups (Facebook, Reddit) for help interpreting results
14. Consider uploading raw data to other sites

Beyond the Basics

Once comfortable with basics:

• Learn chromosome browser
• Study Leeds Method for grouping matches
• Try advanced tools (DNAPainter, Genetic Affairs)
• Join surname projects
• Help others with their research

The Bottom Line

DNA testing is the most powerful genealogy tool available today. For $79-100, you can:

• Discover ethnic origins
• Find hundreds of living relatives
• Break through brick walls
• Confirm decades of research
• Connect with cousins worldwide

Start with autosomal test from Ancestry or 23andMe. Use matches to enhance traditional research. Be prepared for surprises.

Your DNA tells stories your ancestors couldn't write down. Let it speak.

Order your test this week. Your genetic family tree is waiting to be discovered.