When is grandparent DNA testing used?
Grandparent DNA testing is used when the alleged father cannot be tested directly. Common reasons include the alleged father being deceased, missing, refusing to participate, or otherwise inaccessible. The test compares the child's DNA to the alleged paternal grandparents to confirm or exclude a biological connection through their son.
Which grandparents need to test?
Paternal grandparents (the alleged father's biological parents) are the most common testing pair. Including both grandparents produces the highest statistical confidence. When only one grandparent is available, including the child's mother substantially improves accuracy. Our team will explain the right combination for your situation.
How does grandparent DNA testing work?
Call (866) 873-0879
We confirm the right combination of participants and schedule each one.
Visit a collection site
Each participant provides a buccal swab at an AABB-accredited site.
AABB lab analysis
20+ STR markers analyzed; for paternal-line cases, Y-chromosome analysis can be added.
Receive results
Standard 1 to 3 business days. Rush processing available for legal deadlines.
Compare grandparent test scenarios.
Grandparent test scenarios
| Scenario | Participants | Best when | Confidence |
|---|---|---|---|
| Both paternal grandparents | Child + grandmother + grandfather | Both grandparents available | Highest |
| One grandparent + mother | Child + grandparent + mother | Only one grandparent available | High |
| One grandparent only | Child + grandparent | Mother unavailable, single grandparent only | Moderate |
Questions about which option is right for you? (866) 873-0879.
Grandparent DNA testing produces the highest statistical confidence when both alleged paternal grandparents are tested together. When only one grandparent is available, including the child's mother substantially improves the result.
Can grandparent test results be used in court?
Yes. When grandparent DNA testing is performed at an AABB-accredited site under chain-of-custody protocols, results are admissible in U.S. family courts. The collection must be witnessed and identity-verified, and the report is delivered as a certified, notarized document.