There are two basic arguments against capital punishment: that it is morally wrong and that the wrong person might be executed. Death penalty opponents have been able to raise doubts about the guilt of some death row inmates, and DNA tests have shown that at least 68 prisoners, including some on death row (none of whom were executed) were innocent.

But observers say that increasing use of genetic testing will eliminate uncertainty about guilt, shattering the argument based on doubt and thereby strengthening death penalty support. The tests hold the promise of nearly infallible identification.

• Experts say DNA fingerprinting is especially useful in what might be called intimate violent crimes -- in which the perpetrator struggles with the victim and leaves behind blood, semen or something else testable.

• DNA tests are less useful in solving crimes where close contact has not been a factor -- for instance, if the assailant shoots the victim from a distance with a gun.

• Today, only a few states -- New York and Illinois among them -- unambiguously grant those already convicted and imprisoned access to additional DNA testing in attempting to establish their innocence.

• Proponents of testing say other states should swiftly follow their lead -- since a false conviction not only imprisons an innocent person, but lets the real perpetrator go free.

However, in Texas, of the four people on Texas' death row who have been granted extra DNA testing, it has so far failed to clear them or has confirmed their guilt.

DNA fingerprinting will no doubt become widespread, say observers, because the price has dropped dramatically -- from $5,000 when the tests were first developed to about $100 for the newest versions, and is still falling.

Source: Gregg Easterbrook, "The Myth of Fingerprints," New Republic, July 31, 2000.