scoliosis - The cause of scoliosis is poorly understood. In the case of the most common form of scoliosis, Adolescent Idiopathic Scoliosis, there is a clear Mendelian inheritance but with incomplete penetrance. Various causes have been implicated, but none have consensus among scientists as the cause of scoliosis. Scoliosis is more common in females and is often seen in patients with cerebral palsy or spina bifida, although this form of scoliosis is different than that seen in children without these conditions. In some cases, scoliosis exists at birth due to a congenital vertebral anomaly. Occasionally development of scoliosis during adolescence is due to an underlying anomaly such as a tethered spinal cord, but most often the cause is unknown or idiopathic. Contrary to common belief, scoliosis does not come from slouching, sitting in awkward positions, or sleeping on an old mattress.--wikipedia