Scoliosis is an abnormal curving of the spine. While all spines have a natural curve, patients with scoliosis have excessive spinal curving. Usually scoliosis develops during the growth spurt before puberty, between the ages of 9 and 15. Although some cases of scoliosis are congenital, and some are the result of underlying neuromuscular conditions, such as cerebral palsy or muscular dystrophy, most cases of scoliosis are idiopathic, meaning their cause is unknown. Both girls and boys can develop scoliosis, but cases in females are more likely to require treatment. In some cases, scoliosis appears to be hereditary.