IT HAS BEEN less than two decades since DNA was used for the first time to solve a murder. Since then, scientists, the police, those who prosecute crime, and those who defend the accused have found ways to use the twists and turns of this molecule to further their causes. DNA, the molecule that nestles within most cells, has become firmly implanted as a tool of the criminal justice system. Despite its widespread use and its many successes, there are still issues that surround its use. Lawmakers wrestle with how to reconcile the rights of the individual as guaranteed in the Constitution with the welfare of the public as a whole. Other issues concern the practical problems that arise when a new technology such as DNA fingerprinting is in such demand that it becomes nearly impossible to oversee...