This test involves testing two alleged siblings. A siblingship test determines the statistical probability of whether siblings (brothers and sisters) share the same two parents or not. The relationship between alleged siblings, whether half or full, can be established with 15% exclusion and 90% inclusion conclusively. 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 analyse the relationship of biological siblings. Including one common parent greatly increases the accuracy of this type of analysis and is recommended if possible.