A siblingship test determines the likelihood that two individuals are siblings. There are two types of siblingship tests:
- In a full siblingship test, the two individuals are known to share one biological parent (usually the mother), and the test is performed to see if they share the other parent (i.e., they are full siblings).
- In a half siblingship test, two individuals are tested to see if they share one biological parent (i.e., they are half siblings). In most of our cases, we test two individuals with different mothers to see if they share the same father.
Siblingship tests are used to provide additional evidence of family relationships in situations where the alleged father is unavailable for a paternity test. Siblingship tests are also used in verifying biological family members of an adoptee or siblings who were separated at birth.
Siblingship tests can be done using an in-home kit if the results are for personal knowledge only. In-home testing can be ordered online.
If needed for a legal purpose such as immigration, siblingship testing can be performed using a Chain of Custody, a documentation process that makes the test results legally admissible (accepted by courts and other government agencies).
If you would like to take the siblingship test for a legal purpose, please call one of our case managers at 1-888-362-2592 to discuss the legal testing option.
In siblingship tests, the two possible siblings and all available known parents are tested. The probability of obtaining conclusive results is increased when the known parents participate in the test. There is no additional fee for testing parents, except for the sample collection fee.
Unlike paternity, maternity, or grandparentage tests, it is more difficult to achieve conclusive results for siblingship tests. Before we process any payment, our laboratory reviews all requests for siblingship tests, examining all known family relationships to decide whether or not to proceed with the test.
Siblingship tests are complicated by the fact that the DNA portions siblings inherit from their father and mother may be completely different. This is why we strongly encourage the participation of any available, known parents in the test. We can compare the DNA profiles of the siblings to those of the parents and account for some of the differences we observe in the DNA profiles of the siblings.
Results of a siblingship test are reported as a Likelihood of Siblingship. Our laboratory generally achieves a probability of above 90% for an inclusion (the two tested individuals are half or full siblings, depending on the test being performed) or 10% for exclusion (the tested individuals are not half/full siblings). We consider probabilities that fall between 10% and 90% inconclusive. Siblingship tests performed without the known parents may produce inconclusive results.
Painless Sample Collection
Our standard procedure uses the painless and non-invasive buccal swaba cotton-like swab rubbed against the inside of the patient’s mouth to gather loose cheek cells.
Results for siblingship tests are available within 5 working days after we receive samples from all tested parties. In-home siblingship test results are emailed as soon as they are released by the laboratory.
Legal test results are signed by one of Ph.D. scientists, notarized, and sent via first class mail, courier, or fax.