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Unrelated couples can still carry the same hidden condition. Request a carrier check in two minutes.
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The 2026 state-by-state rules, and what the genetics actually say.
DIG DEEPERWhat does your cM mean?
See where your number sits on the centimorgan chart.
How the check works
Every raw DNA file lists hundreds of thousands of markers. We line your two files up marker by marker and look for long stretches where you could have inherited the same DNA from a shared ancestor. The longer and more numerous those stretches, the closer the relationship.
We count stretches of 7 centimorgans or more, the same standard most DNA matching tools use, and we also measure "fully identical" stretches, which is how full siblings stand out from half siblings.
Your privacy, in one sentence
Your files are opened by this page on your own device, compared on your own device, and never sent to us or anyone else.
Check questions.
Is my DNA uploaded anywhere?
No. The comparison runs inside your browser on this device. Your files are never uploaded, never stored and never seen by us. Close the tab and they're gone from the page.
Which DNA files work?
Raw DNA downloads from AncestryDNA, 23andMe, MyHeritage and FamilyTreeDNA, zipped or unzipped. You can mix companies: an Ancestry file and a 23andMe file compare fine.
How accurate is it?
For close relationships it is very reliable. We tested it on simulated families across every file format and the total shared DNA came within about 2% of the true amount, with no false matches between unrelated people. Relationships that share similar amounts of DNA, like first cousins and half first cousins, can't be told apart by DNA alone, so we show the most likely options.
Can it tell full siblings from half siblings?
Yes, usually. Full siblings share large fully identical stretches of DNA. Half siblings, grandparents and aunts or uncles share almost none, even though their totals look similar.
Do we both need to be here?
Both files need to be on the device you're using, so it's best to do it together. That way each of you picks your own file and agrees to the check.
Is this a medical test?
No. It tells you whether you share DNA and roughly how closely you're related. It does not tell you about health risks. For that, see the carrier check.
What does cM mean?
Centimorgans (cM) measure stretches of shared DNA. The more cM two people share, the closer the relationship. See the full centimorgan chart for typical values.