DNA testing is currently the most advanced and accurate technology to determine parentage. In a DNA parentage test, the result (called the 'probability of parentage)[not in citation given] is 0% when the alleged parent is not biologically related to the child and the probability of parentage is typically 99.99% when the alleged parent is biologically related to the child. However, while almost all individuals have a single and distinct set of genes, rare individuals, known as "chimeras", have at least two different sets of genes, which can result in a false negative result if their reproductive tissue has a different genetic make-up from the tissue sampled for the test.