by Joseph Levine and David Suzuki

About the authors: Joseph Levine is a biologist at Boston College and a journalist specializing in scientific topics. David Suzuki is a geneticist at the University of British Columbia and the author of several books.

When Tessie Ashe was eighteen years old, she watched her nine-year-old niece, Farrell, die of cystic fibrosis (CF). In the grip of that fatal genetic disorder, Farrell spent much of her brief life fighting for every breath she drew. Her physical problem was as simple as it was implacable: she was being strangled by her own lungs. The cells lining her respiratory tract, their normal function impaired by a defective gene, secreted a thick, viscous mucus that blocked the flow of air. Farrell was so dependent on supplemental oxygen that she gasped and struggled like a...