Sibling DNA analysis is not as conclusive as paternity DNA test. A sibling DNA test will provide a probability that two individuals are biologically related and can not provide a yes or no answer. On average full siblings will share more genetic markers than half-siblings, and half-siblings share more genetic markers than unrelated individuals. Furthermore, Combined Siblingship Indices (CSI) (probabilities) of full siblings, half-siblings and unrelated individuals sometimes overlap, resulting in uncertainty of the relationship.