Multimethod assessments of temperament were obtained from 89 twins at 18 and 24 months of age. Ratings of subject reaction to restraint and parent ratings of temperament plus coordination of these temperament dimensions with analogous dimensions obtained at 12 months provided evidence of stability of temperament across six-month intervals during…

Examines genetic influences on language by assessing 158 preschool twins on vocabulary comprehension, semantic knowledge, morphology, syntax, and articulation. Vocabulary comprehension was significantly influenced by heredity, whereas performance skills were influenced by between-family environmental factors. (Author/AS)

This study investigated associations between selected infant and maternal characteristics and autism risk in 4381 California children with autism. Increased risk factors were observed for males, multiple births, and children born to black mothers. Risk increased as maternal age and maternal education increased. Children of immigrant mothers had…

This study of 640 twins with reading disability and 436 controls (mean age 12) examined external validity of the distinction between specific reading retardation and reading backwardness, in 3 domains: genetic etiology, sex ratio and clinical correlates, and neuropsychological profiles. There was no evidence of differential genetic etiology of the…