Sibling DNA Testing
DNA siblingship tests determine the statistical probability of whether siblings (brothers and sisters) share the same two parents or not. The cost of the DNA testing service includes two siblings, but you may add more as needed; for instance a third sibling.
When the issue of siblingship is in question, the recommended method to determine whether individuals are true biological siblings is to test their parents. In situations where the alleged parents are unavailable for testing, a DNA siblingship test can be performed to analyze the relationship of biological siblings.
Including one common parent greatly increases the accuracy of this type of analysis and is recommended if at all possible. If this is not possible, disclosing that siblings share a common mother or father can also lead to more meaningful results.
Unlike a paternity test which will always provide a conclusive result, siblingship tests are different. When a siblingship test is conducted, the DNA laboratory will determine the genetic profile of the alleged siblings. Based on the type of genetic material inherited by each sibling, a siblingship DNA index is determined. If the siblingship DNA index is less than 1.00, this indicates non-relatedness. If the siblingship DNA index is greater than 1.00, this indicates that the two tested individuals are more likely to be true biological siblings. The higher the value of the siblingship DNA index, the greater the likelihood that the two individuals are true biological siblings. To analyze the possibility that the siblings share only one common parent versus two common parents (mother and father), a half siblingship DNA index is obtained. The ratio of the half siblingship DNA index versus the full siblingship DNA index would provide you with an idea of whether the two individuals are more likely to share only one common parent (e.g. mother only) or two common parents (mother and alleged father).
Our siblingship tests are preformed using what's known as an "All-vs-All" methodology. For example, if you have two siblings, Alice and Bob, one report will be generated which details the relationship between Alice and Bob. With three siblings you would receive 3 reports which describe the relationships between: Alice & Bob, Alice & Charlie and Bob & Charlie. Four siblings would yield 6 reports: Alice & Bob, Alice & Charlie, Alice & David, Bob & Charlie, Bob & David, and Charlie & David. The amount of reports would subsequently grow exponentially. If you have any questions regarding these reports, please feel free to contact us.
Please note: In some cases, a Y-STR DNA Test can provide more conclusive results for males determining common paternal lineage.
Step 1: Review shipping information
Please review the following important information:
All DNA testing kits are sent complimentary by Express Post. The kits are sent discreetly and there is no mention of "DNA test" kit on the outside of the express post envelope. There is nothing on our return address or packages to indicate the nature of the product inside!
For home DNA test kit orders within Australia:
All kits sent by express post are normally received in only 2 working days.
If you would like your order sent by a courier service, please email us or call one of our Customer Service Advisors for further details on 07 3387 0177.
For home DNA kit orders outside Australia:
GTL Australia is an international company and our partners have administration offices in over 18 countries. We have the ability to send testing kits abroad with ease depending on the type of test required.
Kits can be sent by express mail or a courier service and we will advise the additional costs for you.
If you would like a DNA kit sent internationally, please email us or call one of our Customer Service Advisors for a quote on 07 3387 0177.
When home DNA test kits are shipped:
All orders received by 4pm, Monday to Friday will be dispatched the same day. GTL Australia do not dispatch or receive DNA kits at weekends or on public holidays.
Step 2: Select a DNA test
- Standard testing
Results in 5 - 7 working days (Free of charge)
- Express testing
Results in 3 working days
Review additional information
• Information concerning how samples are taken, the difference between legal and at home testing and more is available for you to read.
Our Refund Policy
Samples must be submitted within 3 months of case initiation or the case will be closed. Refunds will be issued only if applied for within 15 days of the order date. Refunds for orders involving test kits only will not be issued. Full details on our refund policy can be found here.