The SecuriGene At Home DNA Sibling Test is best for individuals looking to determine whether they are full siblings, half siblings, or not related at all. It will not distinguish whether the individuals tested are siblings or cousins.
A sibling DNA test compares the amount of shared DNA between two individuals to determine the likelihood of a full sibling or half sibling relationship.
Full siblings share about 50% of their DNA, whereas half-siblings only share on average 25% of their DNA. Cousins typically share around 12.5% of their DNA. This overlap in the range of shared DNA makes it difficult to differentiate between siblings and cousins through a single DNA test.
If you are looking to distinguish between a Cousin or Sibling relationship, it is best to speak with a specialist about your case. Often, additional parties can be added to the test to strengthen results or to rule out potential relationships. (Additional fees may apply).