Hand preference across time is related to intelligence in young girls, not boys.
Consistency of hand preference was examined in a longitudinal study of children between 18 and 42 months of age. Results showed a sex-specific relationship between hand consistency and intellectual development. Across a variety of intellectual abilities at all ages, females with consistency of handedness were precocious compared to females without such consistency. This relationship did not hold for males.
D002675:Child, Preschool; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007223:Infant; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D012737:Sex Factors; D013997:Time Factors