This paper reviews the research on sex differences in intellectual functioning as it relates to verbal abilities, spatial abilities, and reading aptitudes. Research supports such statements as: sex aptitudes do not become significantly apparent until adolescence; males perform better than females on problems involving field-indep (picking out one image, sound, etc., from many); males seem to have a more favorable attitude toward problem solution than do females; girls' verbal abilities mature more rapidly in early life; and during the period from preschool to early adolescence the sexes are very similar in their verbal abilities, but at about age 11, the sexes begin to diverge, with female superiority increasing through high school and possibly beyond. (TS)