Adolescent idiopathic scoliosis is a highly prevalent disorder of the spine, occurring in phenotypically normal individuals for unknown reasons. The role of genetic factors in this condition has been widely documented through clinical observations and population studies. Multiple areas of research, including connective tissue, neuromotor mechanisms, hormonal system, and biomechanics, have been explored for a potential relationship to the cause of idiopathic scoliosis; however, no clear evidence supports any one area as a etiologic factor of this disorder. The main difficulty of most investigations is to determine whether the observed abnormalities are primary or secondary features in the scoliotic deformity. It is hoped that continued research efforts will aid in the understanding of this disorder in an effort to improve the ability to assign a more specific prognosis.