 In the case of relative borderline cases, the hedge can be shed by the discovery of a novel species of evidence. Murder inquiries were sometimes inconclusive because the suspect had an identical twin. After detectives learned that identical twins have distinct fingerprints, some of these borderline cases became decidable. Presently, there are some borderline cases arising from the extreme similarity in DNA between identical twins. Soon, geneticists will be able to reliably discern the slight differences between twin DNA that arise from mutations.