Siblingship test
$550
Determines whether two people are full siblings, half siblings, or unrelated.
What this test determines
Whether two people are full siblings, half siblings, or unrelated. The test reports the probability of each relationship rather than a simple yes or no, because siblings share a variable proportion of DNA.
Two scenarios are handled:
- Same mother, different or unknown father — the laboratory compares the two people's DNA to determine how likely it is that they share the same biological father.
- Different mothers, same alleged father — the laboratory tests whether the two share a father.
Who this is for
Adults establishing a biological connection where a parent is unavailable to test — for inheritance and estate matters, Social Security or veterans survivor benefits, immigration petitions, or personal knowledge after an adoption or a family separation.
What improves the result
Siblingship is statistically weaker than direct paternity testing. Where a parent is available to test, a paternity or grandparentage test will usually give a firmer answer.
How it works
Collection is a buccal swab. If the result will be used in court, for benefits, or for immigration, book the legal chain of custody — photo identification, photograph at collection, witnessed collection, and tamper-evident sealed transport.
Results are delivered within 2–3 business days of laboratory receipt.
What's included
Two alleged siblings and one mother, strongly recommended. Additional siblings carry an extra fee. Call (206) 883-1850 to discuss your case — siblingship results depend heavily on who participates, and a short conversation before booking often changes what we recommend.