Two thousand, one hundred and eighty-nine southern Chinese women, aged 8–21 years, were studied: 541 with adolescent idiopathic scoliosis (176 treated with posterior spinal fusion and Harrington instrumentation, 150 with brace, and 215 who did not require any treatment), and 1,648 age-matched normal controls from schools and colleges. Scoliotic girls treated at Duchess of Kent Children's Hospital were examined clinically, radiologically, and anthropometrically, including a roentgenogram of the left hand for bone age, at yearly intervals from their first visit to hospital until maturity. Leg:spine and leg:arm ratios were calculated to study the proportionate body growth. The data obtained at first visit and at maturity for each treatment group were compared within treatment groups, and also with normal controls (all age-matched comparisons). The results are summarized as follows: The comparison of leg:spine ratio between fusion, brace, and untreated groups at first visit using uncorrected spinal length showed inconsistent results, but when these ratios were calculated using spinal length corrected for scoliosis, the results were all consistent, showing no significant difference between these groups at first visit. At maturity, leg:spine ratios, using either uncorrected spinal length or corrected spinal length, were highly significantly greater for the fusion group compared to the brace and untreated groups. The leg:spine ratio comparisons of scoliosis groups against normals showed that brace and fusion groups had highly significantly greater ratios at first visit and at maturity, using uncorrected spinal length. Similar comparison using corrected spinal length showed minimum or no difference at first visit, but at maturity, only the fusion group had a significantly greater ratio than normals. The most striking feature within scoliosis groups was that the leg:arm ratios for fusion, brace, and untreated groups were not different at first visit, but at maturity the fusion group had a highly significantly greater ratio than the brace and untreated groups. The total arm lengths for the three treatment groups were similar. The increased leg length in the fusion group was responsible for this increased ratio. Our findings showed that those girls with scoliosis who later required treatment had abnormally increased leg:arm ratios even at first visit, and this lower:upper limb disproportion was greatest at maturity only in those girls who had spinal fusion. These new findings are relevant for etiology, prognosis, natural history, and treatment of adolescent idiopathic scoliosis.