DNA Tests Offer Deeper Examination Of Accused

Civil courts were the first to start admitting and in some cases even compelling second-generation DNA tests. A survey led by Rothenberg and University of Maryland Associate Dean Diane Hoffmann found that in 127 court cases that involved health-related DNA information, more than half had to do with medical malpractice, and most of those were birth-injury claims in which a parent blamed a doctor for a child's neurological or developmental problems. Judges have increasingly granted doctors' requests that such children be tested for fragile X syndrome, the most common form of inherited mental retardation.

The tests can bring much-needed evidence to bear but can also be intimidating -- a potential boon for the doctors. In several instances, parents have either dropped or settled their cases rather than submit their children to a definitive diagnosis that could affect their eligibility for health insurance.

In one case, a mother sued a doctor and a hospital, claiming that negligence during her labor and delivery caused her daughter permanent brain injuries. A geneticist suspected that the girl had Angelman syndrome, a rare disease caused by a defective chromosome. The trial court ordered a DNA test, but the mother refused, resulting in her not only losing the case but also being held in civil contempt.

Similar tactics have been used in "toxic tort" cases, in which people sue alleged polluters for causing their medical problems. In these cases, judges can compel tests that look for the hallmarks of DNA damage caused by certain chemicals.

Plaintiffs have prevailed when the signature DNA injury was found. By contrast, in a case in which a company was sued by people who blamed their various ailments on the company's benzene pollution, the company was found not liable after tests on the plaintiffs did not find the telltale DNA changes caused by benzene.

Measuring a Life Span

Less well developed but potentially more contentious are genetic tests that can help predict how long a person will live.

Anticipated life span can be a big factor when deciding how much a wronged person deserves in money damages -- for example, how much a person might have earned over a lifetime if she had not been disabled by a drunken driver. Toward that end, courts have long admitted crudely predictive evidence such as whether the person already had a terminal disease, smoked cigarettes or engaged in "intemperate habits." Some have even compelled tests for the virus that causes AIDS.

Now life-span testing has expanded into the genetic arena, and not just to calculate damages. In one child custody case, a judge granted the father's request that the mother get tested for the gene that causes Huntington's disease, an inherited and incurable disorder that causes dementia in midlife. Half of individuals who have a parent with the disease carry the ticking time bomb, and most choose not to learn their status in advance. When the judge granted the motion, the mother fled the jurisdiction, giving the father a victory, but not on the merits of his custody arguments.

Many genes contribute to longevity; just last month, researchers announced the discovery of more than a dozen genes newly suspected of helping determine a person's life span. Even if all of them were known, they could at best provide a probabilistic estimate. But as those estimates become more accurate, said Hoffmann, the Maryland associate dean, they will force judges and jurors to think hard about a question that has long dogged legal scholars: Should damage awards be linked to projected life span at all?

"If it's for compensation, then yes, that means you'd want to fine-tune it to the details of the individual and their personal life expectancy," Hoffmann said. "But if damages are about deterrence, then that says you don't get off the hook just because you were lucky enough to hit someone who had a short life expectancy."

Born Criminals?

The stakes are much higher and the ethics more complex when second-generation genetic tests enter the criminal courtroom.

U.S. courts have long recognized that criminal responsibility requires a certain modicum of mental acumen. Beyond the well-known plea of insanity, some states recognize a "diminished capacity" defense. And a 2005 Supreme Court decision barred capital punishment for offenders younger than 18, citing scientific findings of an "underdeveloped sense of responsibility" in minors.