Gene therapy is the use of genes engineered for treating disease. The first human gene therapy was approved for clinical trial in the United States in May 1989. Because this powerful technique is still in the experimental stages, each country has its own approval process, designed to protect the patient, the health workers, and the public. In the United States, each procedure must be approved by the National Institutes of Health's Recombinant DNA Advisory Committee, by the Food and Drug Administration, and by the director of the National Institutes of Health. Gene therapy begins with the isolation of a gene that can have a therapeutic effect, such as producing a protein in patients who lack the protein-producing gene or who have defective genes. In the laboratory, the desired gene is cut out of a cell's deoxyribonucleic acid (DNA) with enzymes. It is then inserted into somatic...