DNA analysis isolates and measures variations in the DNA structure of unknown blood or semen and compares those variations with variations in the criminal suspect's DNA. To maximize the use of DNA analysis in the investigation and prosecution of violent crimes, all specimens must be obtained in compliance with constitutional standards and maintained in a manner that precludes contamination and assures a strict chain of custody for later authentication and identification. When assessing the admissibility of novel scientific evidence such as DNA analysis, some courts limit their review to the application of the traditional evidentiary test of relevancy. Most jurisdictions, however, apply the more stringent Frye standard when judging the admissibility of evidence derived from a relatively new scientific procedure. Accordingly, prosecutors, forensic scientists, and law enforcement officers should satisfy the Frye prescription with introducing evidence based on the results of DNA examinations. They should also anticipate strong defense objections to the admission of such evidence at trial. It is expected that all jurisdictions will recognize the scientific acceptance of the DNA technique after a reasonable period of appropriate appellate review. 31 footnotes.