The g factor is common to all cognitive abilities and to measures of academ
ic performance. An important question in the research on cognitive sex diff
erences is whether, on average, females and males differ in g. This questio
n is technically the most difficult to answer. Furthermore, it has been the
least investigated. In the present study, two samples of young adolescents
solved several cognitive and scholastic (achievement) tests. The samples w
ere a total of 1565 young adolescents (797 girls and 768 boys). Sex was con
sidered to obtain separate g factors. The congruence coefficients between t
he g vectors extracted for each sex suggested a near identity. Then the sex
difference in g was represented on each of the subtests in terms of a poin
t-biserial correlation. These correlations were included with the full matr
ix of subtest intercorrelations for factor analysis, The results reveal the
factor loading of sex on g, which in the present study suggest a null sex
difference. (C) 2000 Elsevier Science Ltd. All rights reserved.