The double-edged helix: advances in genetic testing reveal yet another reason we need national health insurance.

• Author: Townsend, Kathleen Kennedy
• Position: Genetic discrimination could prevent a person from getting disability insurance

A 20-year Veteran of the postal service loses his vision because of a genetic disorder known as Leber's Optic Atrophy. No longer able to work, he applies for and receives disability benefits. But upon a routine review, the supervising government agency cuts off his benefits: Though he had no symptoms when he started as a mailman and, in fact, did not even know of his condition until its onset, the agency says his genetic predisposition for the disease represents a pre-existing condition.

A health insurer denies coverage to a five-year-old boy with a genetic predisposition to heart disease but no symptoms whatsoever. Deducing his condition from the medicine his doctor prescribes to prevent the onset of disease, the insurer says his genetic code disqualifies him for insurance.

A three-year-old boy is diagnosed with MPS syndrome, a genetic disease that causes severe damage to bones, joints, and tissue. The family's private health insurer promptly informs the boy's parents that it is canceling the boy's policy. Diagnosed or not, it says, any genetic disease is pre-existing because the genetic cause has been with the boy since conception.

Welcome to the dark side of the genetic revolution. As with the other great advances in knowledge and technology--the invention of dynamite and the discovery of the atom, for instance--genetic research's enormous potential for good is shadowed by an equally immense potential for harm.

Genetic research is marching forward, uncovering the roots of more and more diseases, and inspiring hope that they may one day be curable. But at the same time, the extraordinary medical benefits are clouded by the fact that gene research now offers insurance companies new ways to trim their expenses by denying coverage to those most in need of insurance.

The promise and peril of the genetic revolution were never in sharper relief than this past summer, when scientists announced they had traced the root of colon cancer to a gene mutation found primarily in Jews of Eastern European descent. The medical implications, of course, are breathtaking Those who carry the gene mutation can get regular colonoscopies to detect the disease in its early, treatable stages. But the same information that may save lives may be used by insurance companies to raise premiums, deny applicants, or cancel coverage for those who carry the colon cancer gene.

The fact that the gene mutation for colon cancer occurs almost exclusively in Jews begs a haunting...