Judges, juries and other members of the criminal justice system rely upon DNA evidence to decide guilt, innocence and sentences for incarceration—and even death—every day. Yet most people would be shocked to learn that new technologies have made DNA evidence less reliable than it was in the past. For instance, recent advances in forensic science use smaller DNA samples, introducing more subjectivity into the identification process than ever before.
Risks of Small Samples
Twenty years ago, available technology could only reliably test DNA from fresh semen, blood stains, or other large tissue samples. According to Christopher Phillips, a researcher in forensic genetics at the University of Santiago de Compostela in Spain, such a test is considered substantially reliable for purposes of forensic evidence.