The first human embryonic stem cell therapy approved by the FDA for human testing has been shown to restore limb function in rats with neck spinal cord injuries - a finding that could expand the clinical trial to include people with cervical damage. In January, the U.S. Food and Drug Administration gave Geron Corp. of Menlo Park, Calif., permission to test the UC Irvine therapy in individuals with thoracic spinal cord injuries, which occur below the neck. However, trying it in those with cervical damage wasn't approved because preclinical testing with rats hadn't been completed.