Forensic DNA Typing, Selected Legal Issues: A Report to the Working Group on Legal Issues, National Commission on the Future of DNA Evidence

Abstract

This report to the Legal Issues Working of the National Commission on the Future of DNA Evidence examines selected legal issues that arise when DNA is employed in criminal investigations and trials. Part I considers the constitutionality of compelling suspects to submit to DNA sampling and of acquiring stored samples of a suspect’s DNA or medical records relating to these samples from private medical providers or laboratories. It also considers the constitutionality of gathering DNA from large numbers of people to see whether any have genotypes that match those seen in the trace evidence. It shows that although the Fourth Amendment usually requires the police to have probable cause and a warrant to compel a person to provide a DNA sample, there are many situations in which police may be able to secure DNA samples without these safeguards. Part I also considers a second investigative use of DNA — deducing physical or other characteristics of an individual whose DNA is found at the scene of crime. Genetic typing will permit inferences as to ancestry, physiognomy, or inherited disorders. Part I concludes that investigators can use genetic data to make valid inferences without infringing any constitutional rights. Part II discusses the admissibility of new DNA tests and the results of proficiency tests at particular laboratories. It suggests that the rules of character evidence create a largely unrecognized, and probably undesirable, obstacle to admissibility. It also considers suggestions that the durability of DNA evidence justifies extending the statute of limitations for prosecutions for certain crimes. Here, we counsel caution and careful weighing of the competing considerations before any legislative action is taken to extend the period of criminal responsibility. Part III explores constitutional and ethical questions that must be confronted in establishing and operating DNA databases for law enforcement purposes. It also indicates the array of policy choices that must be made in developing these systems — from the determination of which individuals are subject to having their genotypes placed in the databank, to the specification of how the DNA samples are obtained, to the decision as to how long the samples should be retained, and to the enumeration and definition of the uses to which the information may be put.