Sibling to sibling relationship

Are you half sibling or full siblings? If you are half siblings you will share around half of your genetic material and share only one biological parent. If you are full siblings, then you will usually share the vast bulk of your genetic material and thus, share both biological parents.

Are you half siblings or no siblings? If you are not siblings at all you will have very little, if any, genetic material in common (any similarities in DNA are likely due to chance. All of us share similar DNA to some extent or other).

A siblings DNA test is done in cases where direct comparison of parent-child DNA is not possible by means of a paternity DNA test or maternity DNA test.  We strongly suggest sending in a sample of a known parent if available.

Notes about siblings DNA testing

We strongly suggest including the sample of a known mother to provide stronger results.

Siblings DNA testing is carried out when test participants are male and female. In cases where testing takes place individuals of the same sex, we have other more suitable tests.

Different types of tests between siblings

  • X Chromosome test – a DNA test that will determine whether two females share the same father; the test must be carried out with inclusion of mother’s sample if females share the same mother. If females being tested do not share the mother, the same of the mother is not required
  • Y Chromosome test – a DNA test that will establish if males share the same father; this test is highly suited to male siblings who need to establish if they share the same father.
  • MtDNA test – this test is done to confirm whether siblings or individuals tested share the same maternal line.  The results are accurate but simply confirm whether tested parties share any, possible, direct maternal ancestor in common.