Last updated on: 8/19/2008 | Author:

Has DNA Testing Led to Significant Improvements in the Criminal Justice System?

PRO (yes)


Stuart Taylor Jr., JD, Nonresident Senior Fellow of Governance Studies at the Brookings Institution, in his Nov. 17, 2007 National Journal article “The Death Penalty: Slowly Fading?,” wrote:

“Irrefutable DNA evidence has exonerated some 15 death-row inmates and almost 200 other men convicted of murder or rape, mostly since the late 1990s.  This DNA-evidence revolution, along with non-DNA evidence proving the innocence of a great many more condemned men and other prisoners, has alerted many who support the death penalty in principle to the fallibility of the criminal-justice system and the risk of executing innocent people.”

Nov. 17, 2007 - Stuart Taylor, Jr., JD


Orrin G. Hatch, JD, US Senator (R-UT), in his June 13, 2000 speech “Statement of Senator Orrin Hatch Senate Committee on the Judiciary Hearing on ‘Post-Conviction DNA Testing: When Is Justice Served?’,” stated:

“Advanced DNA testing improves the just and fair implementation of the death penalty. While reasonable people can differ about capital punishment, it is indisputable that advanced DNA testing lends support and credibility to the accuracy and integrity of capital verdicts. In short, we are in a better position than ever before to ensure that only the guilty are executed. All Americans — supporters and opponents of the death penalty alike — should recognize that DNA testing provides a powerful safeguard in capital cases. We should be thankful for this amazing technological development.”

June 13, 2000 - Orrin G. Hatch, JD


The American Civil Liberties Union (ACLU), in its June 26, 2002 article “DNA Testing and the Death Penalty,” posted on, wrote:

“The increasing use of DNA testing to help confirm the innocence or guilt in capital cases is one among many reforms that will help ensure that innocent people are not sentenced to death…

Unique to an individual (except in the case of identical twins and bone marrow transplant recipients), unchanging throughout one’s life, and found in all one’s cells, DNA is a reliable identifier. DNA testing on biological samples such as skin, saliva, semen, blood or hair can help convict or exonerate with great accuracy. But only if the biological evidence is properly collected, preserved and kept from contamination. And only if the analysis is done correctly. Under those conditions DNA testing is the modern improved version of fingerprinting.”

June 26, 2002 - American Civil Liberties Union (ACLU)


The National Institute of Justice, in its Sep. 1999 report “Postconviction DNA Testing: Recommendations for Handling Requests,” wrote:

“In little more than a decade, DNA (deoxyribonucleic acid) evidence has become the foremost forensic technique for identifying perpetrators, and eliminating suspects, when biological tissues such as saliva, skin, blood, hair, or semen are left at a crime scene. First introduced into evidence in a United States court in 1986 and the subject of numerous court challenges in the ensuing years, DNA evidence is now admitted in all United States jurisdictions…

Moreover, law enforcement agencies and legislatures have come to understand the potential of using DNA testing systematically by constructing DNA databases on a State and Federal level that inventory DNA profiles from new unsolved cases, old unsolved cases, and convicted offenders. As these DNA databanks grow in size, society will benefit even more from the technology’s incredible power to link seemingly unrelated crimes and to identify with alacrity suspects who were until then completely unknown to investigators…

A remarkable feature of DNA testing is that it not only helps to convict but also serves to exonerate. A 1995 survey of laboratories reported that DNA testing excluded suspects in about one-fourth to one-fifth of the cases…These suspects were fortunate: Before the advent of DNA testing they might have been indicted on the basis of an eyewitness’ statement or other evidence and possibly been convicted on the basis of such proof.”

Sep. 1999 - National Institute of Justice (NIJ)


Walter F. Rowe, AM, PhD, Professor in the Department of Forensic Sciences at George Washington University, in the National Institute of Justice’s June 1996 research report “Convicted by Juries, Exonerated by Science: Case Studies in the Use of DNA Evidence to Establish Innocence After Trial,” wrote:

“The introduction of DNA profiling has revolutionized forensic science and the criminal justice system. DNA technology has given police and the courts a means of identifying the perpetrators of rapes and murders with a very high degree of confidence…

For a variety of reasons, DNA profiling has significantly advanced the analysis of biological stain evidence. First, these methods are intrinsically more discriminating than the methods of genetic marker analysis heretofore used. DNA profiling is more likely to exonerate a wrongly accused suspect. Second, the DNA molecule is more stable than polymorphic proteins. Third, microbial degradation does not lead to erroneous typing results.”

June 1996 - Walter F. Rowe, PhD


Rolando Cruz, Charles Irvin Fain, Ray Krone, Ryan Matthews, Curtis McCarty, and Earl Washington, former death row inmates exonerated by DNA evidence, in their Dec. 20, 2007 letter to the Governor of the State of Alabama Bob Riley, wrote:

“We write to you today because we were all convicted and sentenced to die for crimes we did not commit, only to be exonerated years later through DNA testing.

In each of our cases, juries heard evidence they believed was overwhelming and proved our guilt beyond doubt. Prosecutors, judges or governors rejected our initial pleas for DNA testing. Each of us sat on death row, wondering whether the truth would come out before we were executed. And each of us was spared when the irrefutable science of DNA proved that we were innocent…

If we had never been granted DNA testing, we might not be alive today.”

Dec. 20, 2007 - Letter to Governor Riley

CON (no)


Gwendolyn Carroll, JD, former Editorial Staff of The Journal of Criminal Law & Criminology, in the publication’s Winter 2007 article “Proven Guilty: An Examination of the Penalty-Free World of Post-Conviction DNA Testing,” wrote:

“[P]ost-conviction DNA testing, more often than not, provides either inconclusive results or, in many cases, confirms the guilt of the prisoner seeking testing. In addition, DNA testing is costly, time-consuming, and provides an additional administrative burden on already over-extended state criminal justice systems.”

Winter 2007 - Gwendolyn Carroll, JD


Richard C. Dieter, MS, JD, Executive Director of the Death Penalty Information Center, in the Sep. 2004 Death Penalty Information Center report “Innocence and the Crisis in the American Death Penalty,” wrote:

“The era of DNA testing has not ushered in a fool-proof criminal justice system. It is not true that the problems of wrongful convictions are in the past and will not happen anymore because technology can now precisely determine guilt. Nor is it true that the death penalty can proceed unchecked under the assumption that all the inmates on death row have had ample opportunity for DNA testing…

DNA exonerations represent only 12% of the total list of 116 cases. In 88% of the cases, attorneys and courts had to rely on other forms of evidence…

Many states have not passed legislation guaranteeing the right to DNA testing. Even where this right is protected by statute, such as in Texas, there are stringent limits on its use and inmates have been refused testing where the results might have affected the death sentence, even if not the determination of their guilt…

Shouldn’t DNA testing ensure that only the guilty are being convicted and sentenced to death? This is not the case because most murders do not involve the exchange of bodily materials containing DNA evidence…Wrongful convictions will continue to occur as long as our criminal justice system utilizes human actors.

When newly tested DNA evidence is presented after an inmate has been convicted and sentenced to death, it is usually checked and rechecked before that inmate is ever set free. However, it appears that the same reliability cannot be attributed to the pre-trial DNA testing that can often result in a conviction and a death sentence. Recent scandals from crime labs in many parts of the country have exposed the risk of wrongful convictions that shoddy forensic work can bring.

The performance of pre-trial DNA testing is not always a reliable source of forensic information. If evidence is contaminated at the scene of the crime, if the police are not skilled in the collection of such evidence, if the police lab that performs the testing is unqualified to render reliable results, or if the state’s expert is incompetent or dishonest, then evidence presented under the veil of scientific certainty becomes the very source of misinformation leading to mistake.”

2004 - Richard C. Dieter, MS, JD


Ellen Kreitzberg, JD, Professor of Law at Santa Clara University, in a May 7, 2001 Ethics Today interview conducted by David Perry and aired on KSCU Radio Station, stated:

“The DNA testing and evidence only occurs in a situation where the assailant leaves biological evidence behind. For the most part, we are talking about rape cases where there is semen left that can be tested. There are occasionally non-rape cases where the assailant may have left behind hair fragments or fingernail fragments that are of a sufficient quantity that they can be tested for DNA. But if no biological evidence is left behind, which is what occurs in most cases in the criminal justice system, no DNA testing can occur. The second qualifier is: even among those cases where there is biological evidence left behind that can be tested, if it is not gathered and collected and preserved properly, you will end up with a false test.

So I think the possibilities with DNA testing are immense in terms of being able to exonerate certain people, or on the other hand, definitively indicate that they were the perpetrator. But it still will not be available in somewhere between 70 and 75 percent of the cases in the criminal justice system, perhaps even more. So it is not the silver bullet that is going to solve our criminal justice system problems.”

May 7, 2001 - Ellen S. Kreitzberg, JD


The Economist, in its Dec. 12, 2002 article “A Pandora’s Box,” wrote:

“Good DNA material is available in only one in five felony cases: often there is not enough DNA for a sample, or it is old or contaminated. And it is not necessarily proof of guilt or innocence. You can commit vicious crimes without leaving physical evidence behind (as some argue the teenagers did in the Central Park rape case).

Although DNA tests back up convictions roughly half the time, politicians have been slow to embrace a tool that has mainly hit the headlines when it has revealed miscarriages of justice. As recently as 1999, only two states had laws allowing post-conviction DNA tests. Twenty-six have such laws now, but many impose arbitrary restrictions. In Kentucky, only inmates on death row qualify for a post-conviction DNA analysis. And getting such analysis is a haphazard business. Mr King’s reprieve was the result of a month-long campaign, at the end of which Mr Scheck (who defended O.J. Simpson) inveigled his way into the governor’s office.

Cost plays a part. Laboratory tests on older forensic evidence can cost thousands of dollars. But the main reason seems to be fear. For law-enforcers, DNAanalysis is a Pandora’s box: each new ‘criminal’ proved innocent opens up more doubts about the system that convicted him.”

Dec. 12, 2002 - The Economist