HIS BROTHER'S KEEPER

A Story From the Edge of Medicine

By Jonathan Weiner. Ecco. 356 pp. $26.95

Jamie and Stephen Heywood are companions and cocky, affectionate rivals, in the familiar way of brothers born two years apart. In their brainy, close-knit and taciturn New England family, play is the language of love. As boys, they sneak out together to ride the rapids on a creek during a storm or to play night laser tag in the woods. As young men living in different cities, they spar online in computer games. At every family gathering, they arm-wrestle. Oddly, it is Jamie, the older one, who takes these duels seriously and cares about the outcome. So it is Jamie who crows with glee one summer day when, to his surprise, he forces his carpenter brother's mighty right arm to the table. Neither man realizes that Stephen's defeat is no fluke, but the first indication of a dreaded ailment: amyotrophic lateral sclerosis or ALS, also called Lou Gehrig's disease. Within two years, Stephen will be diagnosed with early signs of a nerve-destroying paralysis that slowly robs its victims of strength until they can no longer talk, then can no longer breathe.

Jonathan Weiner is a Pulitzer prize-winning science writer whose previous subjects have been biologists intellectually obsessed with finches and fruit flies. Jamie Heywood, the central figure in Weiner's superb new book, is also obsessed -- but what drives Jamie is love and a "maddening hope." When his younger brother develops ALS, the dream of engineering and delivering a cure to save Stephen becomes the organizing principle of Jamie's life. The hubris of his quest is all the more breathtaking because he is not a scientist, but a charismatic young entrepreneur watching from the sidelines at an especially optimistic moment in scientific history.

Even as weakness creeps up and down Stephen's limbs, possible genetic fixes are being cobbled together and readied for testing in dozens of diseases. Jamie asks, Why not for Stephen? If Stephen Heywood had fallen ill a decade earlier, reputable doctors and researchers would have summarily dismissed Jamie's scheme to devise an experimental gene therapy for ALS and try it on his brother. But in the late 1990s, several highly regarded scientists and physicians listen and agree to become acrobats in his high-wire act.

In His Brother's Keeper, the biology of nerve cells and the dawning history of gene therapy play supporting roles in a plot as finely crafted as that of the best novels. Weiner uses the Heywoods' story to illuminate the unexpected ways in which a serious illness reveals character and shifts the balance within a family. Stephen Heywood is both brave and enigmatic: The center of a storm, he manages to downplay the terrifying reality of his disease while staying solidly connected with those he loves. The Heywood parents, John and Peggy, lend financial and emotional support to Jamie's headlong campaign but seem to remain clear-eyed, without false hopes. Jamie's wife, Melinda, and Stephen's fiancee, Wendy, give voice, aloud and in their journal scribblings, to the fear, guilt and anger of which the Heywoods themselves never speak.

But it is Jamie who fascinates. He draws the reader into Weiner's tale the way he drew scientists onto his team -- and drew Weiner himself into his family and into his obsession. Jamie's brilliance and energy are at first dazzling, then unsettling. The longer Weiner follows the story, the more ambiguous Jamie's motives appear, and the more bizarre seems his wish to inject a virtually untested treatment into his brother's nervous system. Meanwhile, the nation's early optimism about gene therapy is dashed by the death of a teenager in a medical experiment in Philadelphia, the same city where Jamie's scientific collaborators have been busily engineering genes to treat Stephen's ALS.

Weiner has a master's eye for the telling detail and a spare, often poetic style. His terse recounting of the seminal advances and setbacks in genetic engineering in the late 1990s provides the scientific counterpoint to the Heywood family drama. His Brother's Keeper could be considered the third volume of a trilogy that began with The Beak of the Finch, Weiner's chronicle of biologists watching bird evolution in the Galapagos, and continued with Time, Love, Memory, his probing of the genetic basis of behavior. In this book he brings the biology home, asking whether the revolution in our understanding of genetics can and should be harnessed at will to save a brother or to create a child.

The larger question is whether we will be able to use what we are learning to make us more fully human, or whether our new knowledge and power will obstruct that journey. "I wanted what I had seen and felt when I was small to have some connection with what I would see, learn and know in the end," Weiner writes. "I thought the whole human race wanted something like that. The beginning, middle and end should make one unbroken story. The stem should lead up to the rim of a cup from which we can drink and still be ourselves." *

Susan Okie is a science reporter currently on leave from the Washington Post. Her book about fighting the childhood obesity epidemic will be published in early 2005.