A federal report says DNA fingerprinting should not be allowed in court until laboratory standards have been tightened and a firmer scientific basis for the method is established.
The report by the National Academy of Sciences also says the genetic technique for identifying criminal suspects must be regulated and controlled by scientists and federal agencies that have no stake in the method's success.
In principle, the technique, known as DNA fingerprinting or DNA typing, allows a person to be identified from the tiniest scraps of body tissue at the scene of a crime, whether a drop of dried semen, a strand of hair or a spatter of blood. The technique relies on the fact that each person's DNA, the genetic material, is unique.
Noting that serious questions had been raised about the way DNA fingerprinting has been used, the report, to be issued Thursday by 12 scientific and legal experts, says the technique is potentially too powerful to be left solely in control of prosecutors and law enforcement officials.
Ever since DNA typing was introduced in American courts in the late 1980s, it has been the subject of bitter disputes. The technique has been vigorously embraced by some prosecutors because of its scientific basis and persuasiveness to juries. But defense lawyers have often fought it because they fear it could persuade jurors to overlook other evidence.
Most courts have agreed to admit DNA evidence and hundreds of cases that relied on DNA fingerprinting have been tried.
But critics have argued that the method is not as conclusive as it appears and that it is not yet ready to serve as evidence in court.
Some legal experts said the report would have an immediate impact. Dr. William Thompson, a lawyer and molecular biologist at the University of California at Irvine, said the report "raises serious concerns about whether DNA tests as they are currently done meet the standards for admissibility in court."
Dr. Thompson, who has testified for the defense in cases involving DNA, added that although the committee carefully avoided commenting on DNA cases that had already gone to trial, the recommendation that courts in the future insist on strict scientific standards "is a very subtle and cautious way of saying we were too hasty."