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Science in the Courtroom

The O.J. Simpson trial brought home to millions around the world the degree to which DNA fingerprinting and other laboratory sciences have begun to influence decision-making in the courtroom. In some cases, DNA tests have even led to the release of death-row prisoners whom the tests have exonerated. In this interview, Judge Paul Chernoff of the Norfolk Superior Court in Massachusetts, who organized and attended a recent seminar on DNA given for Massachusetts Superior Court justices at Boston's Whitehead Institute for Biomedical Research, describes the experience and why he feels it is vital that judges be schooled in these novel techniques.



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Scientific techniques such as DNA fingerprinting are increasingly being used on evidence presented in courtrooms. Judges should be familiar with such techniques, says Judge Paul Chernoff.
© Frances Twitty/iStockphoto

Judging science

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NOVA: Have you had to rule on any cases involving DNA analysis?

Chernoff: Only in blood and semen matching on a couple of serious sexual assault matters. In one case, it actually ended up exculpating the individual. A woman who was sight-impaired identified her attacker by his voice, and then the DNA testing of his blood versus the semen or sperm found in the woman excluded him absolutely and positively, and he was acquitted. And, you know, that's what Attorney General Janet Reno is concerned about. She thinks the real potential for DNA is to free the innocent, and not to necessarily inculpate the perpetrators, although it certainly works to that effect, too.

Why is it important that judges be up on DNA analysis in forensics?

Well, I think there are at least four reasons why we should be, because the subject can visit us in at least four ways, probably even more. The first way is that, in ruling on admissibility of evidence on a case-by-case basis, this technique comes across our benches now and will continue to do so. It's especially important in criminal cases, because it can exclude or inculpate an alleged perpetrator.

The second way is that DNA is such a powerful tool for potentially understanding human behavior, and we're certainly going to see it on that plane. Last week during a case's sentencing, for instance, it was brought to my attention that the defendant had a certain genetic abnormality, which I was asked to consider in the sentencing decision.

"All this goes far beyond what fingerprints and hair samples can reveal," Judge Chernoff says of DNA testing and other advanced forensics.
© Hans Laubel/iStockphoto

The third area deals with the right of privacy, and already we've experienced that. The very taking of samples, the access of individuals to a database, the use and misuse of the data—all this goes far beyond what fingerprints and hair samples can reveal.

"I just looked at this gelatinous stuff and said, 'My God, that's DNA.'"

The last area is perhaps the most important. It hasn't come to us yet, though we've seen that people in other facets of government, meaning the legislative and executive branches, are often concerned about the potential of this very, very powerful science and whether or not government should regulate it in any way. As the potential for what can be done with this becomes more and more known, I think we judges are going to find ourselves as referees between government and science.

Should judges have an in-depth understanding of such scientific techniques, or would a basic understanding suffice?

I think a basic knowledge would suffice. We in the Superior Court, and I think most judges in courts of general jurisdiction, are generalists, and we're expected to be quick learners, whether the subject matter is science or sports or industry. We should be able to learn it rather quickly.

Justice in class

So what was it like getting a lesson in DNA analysis?

For me, and I think I speak for all of my colleagues, it was really a happening. We had hands-on laboratory experience. In judicial education, we're subjected to a traditionally academic environment, and there's very little chance for hands-on education. Another thing was a little surprising to me. We were forewarned at the beginning that many of us would find it to be an "existential moment" when we completed the laboratory steps and found ourselves face-to-face with actual DNA. And you know, it was. I, among others, just looked at this gelatinous stuff and said, "My God, that's DNA."

DNA results
The use of results from DNA studies on the blood of both victims and attackers alike has become commonplace in modern courtrooms.
© Zmeel Photography/iStockphoto

Did you find the science daunting, or did it all make sense?

Well, it was both daunting and approachable. Whether or not it made sense I'll reserve for another day, but the very basics and the overviews certainly made sense to us. We learned that we're trainable, and that with future programs we could come a long way on this. When you think about it, the amount of progress that a group of 25 of us made in just two days under the guidance of a handful of talented young scientists was impressive. I was pretty pleased with how it went, and so was everyone else. We were struck with how young these scientists appear; they were all 25 to 30 years old.

Science and law

What do you think is the biggest challenge that science and law will have to face together with DNA?

Coping with the specter of an almost infinite amount of information. I don't think we can imagine how much data will be developed and need to be stored and dealt with over time. I don't even know if we've got the mechanism for storing it, and I don't know what the security concerns are, but it's certainly not like having 10,000 fingerprint cards in a file. It's information that will fill up any computer resource and then some. It's going to be more information than we can handle. That's a real problem that science and the courts have to deal with.

Also, I'm not sure who should have access to that information. There will be some very disturbing information about a lot of people, which maybe no one should have a right to have. A number of jurisdictions have programs like we have in Massachusetts, in which offenders in certain categories have to give samples for DNA. That information then gets typed and stored. Most jurisdictions don't have the capacity for storing and classifying that information. And that's just the tip of what's going to be a very, very big iceberg.

"If you're not being square with your test results, it doesn't matter how good the process is."

Another interesting thing about the potential of DNA and the potential of storing all of this information is that when people plead guilty now, we tell them that the government has the right to take a sample of their DNA, and that data will then be stored and used for government purposes. It's like a super fingerprint.

Even such a simple act as shaking hands can complicate the presentation of genetic evidence, since an individual's DNA can be transferred that easily.
© webphotographeer/iStockphoto

If DNA fingerprinting is so seemingly perfect, are you taking the human element out of it?

No, I don't think so. Portions of the science are so exact that it makes us really focus on the human aspect of it. We know that the science of identification—comparing one person's DNA with another person's DNA—approaches a near certainty. I think it's one in three billion for including or excluding someone. And so that part of speculation or inference is really eliminated.

But it forces us to focus on other factors, including how evidence is collected. There's plenty of room for someone to make a mistake in the collection of data, and there's plenty of room for human deviousness. You know, if you're not comparing the right substances, if you're not being square with your test results, it doesn't matter how good the process is. So the human element is still there.

This folds into the daunting aspect as well. One of the things I learned is that, for example, if you and I shake hands, some of my DNA rubs off onto your hand, and some of the cells from your hand rub off onto mine. If I then go and pick up a telephone, your cells may end up on that telephone, and if there's a DNA match with cells on that phone, someone might think that that is evidence that you touched that telephone.

Judges today must be conversant in a wide range of fields, from DNA fingerprinting to psychopharmacology.
© Pierre Desrosiers/iStockphoto

Whether that's good science or bad science, or a good conclusion or a bad conclusion, it creates a real problem for us. If it is true that evidence could be admitted that your cells are on that phone, it means that the technique is not really as perfect as it may appear, because you can get cells transferred so easily. If it's not true, and it's all smoke and mirrors, then it's smoke and mirrors that somebody can blow at valid DNA evidence, and it can trivialize it when it shouldn't. That's a little daunting as to how we would handle that kind of issue in court.

Bench work

What other scientific techniques or procedures are increasingly playing a role in court cases?

Well, pharmacology and psychopharmacology—the use of drugs, and how they affect people. I don't think that has much to do with DNA, although it might, if you compare how drugs work on different people. I'm sure there may be some genetic aspect to that. But whether or not a person who is incompetent for trial, or incompetent to plead guilty, can be made competent at least temporarily by the administration of certain drugs—that's a very big issue for us.

Also whether or not you can mandate that someone take a particular legal drug that might make the person more stable, and thus make you more willing to take a chance on them as far as sentencing is concerned. Then, of course, how do you enforce that in the community, to make sure that a person takes that drug? I think that's a real challenge for us, to understand the pharmacology of legal and illicit drugs. A lot of people that we see who come before us on the criminal side are constantly under the influence of a drug, or they've been under the influence, or they will be under the influence.

polygraph test
"It was a wonderful experience for me to look at the entire science behind the polygraph and determine whether it should go or not," says Judge Chernoff.
© Ocean/Corbis

Have you found that you've had to judge a scientific technique or procedure itself while judging a case?

Yes, I held a hearing on polygraph testing and found it to be somewhat valid, somewhat invalid. I carved out a mechanism for handling it in court that I thought made perfect sense, but the Supreme Judicial Court disagreed. Nevertheless, it was a wonderful experience for me to look at the entire science behind the polygraph and determine whether it should go or not.

More recently, I had to rule about testimony concerning the blood/brain barrier, specifically on the issue of whether or not myotrauma can exacerbate multiple sclerosis. The Multiple Sclerosis Society says no, a Harvard doctor says yes. The question was: Should those competing experts be able to testify before a jury? I ruled that they could (and the jury ruled against the plaintiff in the case). But I had to rule on the science. Whether or not the theory was correct or not is not the issue; it's whether or not there's validity to the theory and reliability to the method. And whether the expert's right or wrong is not for me but for the jury to decide.

"I think maybe we started something here."

There's another interesting thing I took away from the two-day program at the Whitehead Institute. We as judges have focused on DNA as a law-enforcement technique to either include or exculpate an individual, but we quickly learned in our program that that's just a fragment of the science. What it's really going to yield, we hope and expect, is the promise for curing disease and making diagnoses and relieving human suffering. This wonderful DNA matching is a nice spin-off for law enforcement, but it's the rest of the science that really has more importance in the long run for human beings.

Judge Paul Chernoff
Just as he learned a lot visiting a laboratory, Judge Chernoff, seen here in 2010, believes scientists could learn a lot from visiting courtrooms and seeing how science is treated there.
AP Photo/Mark Garfinkel, Pool

Future case

So what's your next seminar? Do you have one planned?

We've been talking with the Whitehead people about a joint training program for scientists and judges, in which we would bring them this time into our laboratory, the courtroom, and show them how science is treated there. We would have them school us on science, and we would school them on legal procedure and on how validity and reliability are resolved in a court of law.

Is this kind of judges-go-to-school program unusual in the U.S. judicial system?

It is. I've been told that, aside from the Whitehead Institute, there are only two programs in this country. The Cold Spring Harbor Lab on Long Island has offered an educational opportunity to the judiciary in New York, which focuses on some of the issues we learned about. And George Washington University in Washington, D.C. has a couple of day programs for judges, though I don't know if they have the laboratory component. One of my colleagues, who like me is on the faculty of the Judicial College in Nevada, was out there the week after the Whitehead program, and people there had learned of the program and were very interested in learning more. They would like to hook up with a college or university in California to try to bring some of their scientists to the Judicial College to school judges. So I think maybe we started something here.

Editor's Notes

This feature, which was reillustrated in 2011, originally appeared on the site for the NOVA program Killer's Trail.

Major funding for NOVA is provided by the David H. Koch Fund for Science, the NOVA Science Trust, the Corporation for Public Broadcasting, and PBS viewers.