Families come to sibling testing for many reasons: an absent parent, an adoption, an inheritance question, or simply wanting to know. A siblingship DNA test evaluates whether two or more people likely share biological parents.
Full siblings vs. half siblings
- Full siblings share both biological parents.
- Half siblings share one biological parent.
The laboratory compares the participants' DNA and reports how strongly the results support one relationship over another, for example full siblings vs. half siblings, or half siblings vs. unrelated.
Who should participate
Each sibling being tested provides a cheek swab. If a known parent (often the mother of one or both siblings) can participate, the laboratory can usually produce a more conclusive result. Let us know who is available and the laboratory will advise.
Legal or personal use
Sibling testing is available as a legal test with chain-of-custody documentation, or a non-legal test for personal information. Legal reports may be useful for inheritance, benefits, or immigration matters, but the requesting court or agency decides what it accepts.
What to expect from results
Sibling relationships are more complex to evaluate than parent–child relationships, so results are reported as likelihoods and occasionally are inconclusive. Adding participants can help.
Pricing and booking
Sibling testing is $475 for a legal test and $395 for a non-legal test, with laboratory results typically in 1–2 business days. Learn more on our Siblingship DNA Testing page or book an appointment. We collect specimens at a mutually agreed-upon public meeting location and a certified laboratory partner performs the testing.
This article is for general education and is not legal or medical advice.