Sibling DNA Testing
Sibling DNA testing can help confirm whether two individuals share one or both biological parents. Whether it’s for legal reasons, family peace of mind, or after discovering a surprising ancestry result, sibling DNA tests provide scientific clarity.
Why Someone Might Use a Sibling DNA Test
You’re trying to confirm if you share both parents or just one
The alleged parent is not available for testing
You’re adopted and trying to confirm a biological relationship
You're pursuing immigration, inheritance, or citizenship documentation
Full Siblings vs. Half Siblings: What’s the Difference?
Full Siblings: Share both biological parents
Half Siblings: Share only one biological parent (mother or father)
Sibling tests use autosomal STR (Short Tandem Repeat) markers to compare the amount of shared DNA and calculate the likelihood of full or half sibling status.
What Affects Accuracy?
Type of Relationship: Full siblings typically share more DNA markers than half siblings
Additional Participants: Including a known parent (typically the mother) increases accuracy
DNA Quality: Clean, well-preserved swabs yield better results
Sample Collection
Use the cheek swabs provided in the kit
Avoid eating or drinking 30 minutes before collection
Label each sample clearly to avoid delays
Each participant should have their own envelope. DO NOT mix the samples together.
View Sample Collection Instructions
Understanding Your Results
Results are presented as a percentage indicating the likelihood that two individuals are siblings:
Above 90%: Strongly suggests a sibling relationship.
Below 10%: Strongly suggests no sibling relationship.
Between 10% and 89%: Inconclusive, requiring further investigation, such as including a known parent's DNA sample.
Results will include a Likelihood Index:
Greater the number given the greater chance of a biological relationship exists
FAQs
Q: Can a sibling test replace a paternity test?
A: It can be used when the father is unavailable, but it’s less direct and may require additional participants for certainty.
Q: Can you tell which parent you share?
A: Not precisely. The test tells you if you share one or both parents, but not which parent specifically.
Q: How accurate is the Sibling DNA test?
A: This test is 99.9999% accurate (the highest scientifically possible).
