Paternity For Life

Sibling DNA Test

A Sibling DNA test is recommended where two alleged siblings (male or female) wish to confirm if they share a biological parent. A Sibling DNA Test will determine the likelihood that the two persons tested are siblings based on the amount of common DNA shared between them.

Sample Collection Process

For Relationship DNA Testing, samples can be collected by the individuals to be tested themselves, at home. Paternity for Life uses mouth swabs for a simple and painless collection process. Upon receiving your application and payment, Paternity for Life will send a collection kit to your nominated address. This kit will contain everything you need to collect the samples, along with clear instructions on how to do so. Once the samples have been collected, they are then returned to us in the supplied return envelope.


Results will be available within 5 working days, from when we receive your samples at our laboratory. Results will only be sent to the parties being tested (or their legal guardian), to the email addresses provided at time of sample collection. A hard copy of your results can also be arranged (additional fees apply).

Understanding Your Results

Unlike Paternity or Maternity DNA testing, Extended Relationship DNA Testing cannot give a conclusive result of whether or not a relationship exists between the persons being tested. This is because Extended Relationship tests involve comparing less direct relationships than that of a parent and child. A child will inherit 50% of their DNA from each parent, allowing for a conclusive result to be given in the case of Paternity or Maternity. Siblings will share a lower percentage of DNA.

Instead, the results will show the likelihood of a relationship between the tested persons based on the amount of common DNA.

  • A likelihood ratio less than 1 – a relationship is unlikely to exist.
  • A likelihood ratio greater than 1 – It is likely that a relationship exists. The greater the number above one, the greater the likelihood the persons tested are related.

If you are unsure of the DNA test you need, please contact us to discuss your particular case. We can help determine which test would be best suited for you based on what it is you are looking to confirm through DNA testing and what the alleged relationship is between the persons to be tested.

Paternity For Life advises that the results may be inconclusive for an Extended Relationship DNA test. This is not due to laboratory error, but as explained above, due to the difficulty in comparing individuals in extended relationships.
Please note: No testing costs will be refunded in the case of an inconclusive results.

Sibling DNA Test For Brothers

If the siblings wishing to be tested are both males and want to determine whether they share biological father, a Y Chromosome Test may be better suited.



Paternity DNA Testing Lab