Five sex-steroid hormones (testosterone, androstenedione, estradiol, estrone, and progesterone) were assayed in umbilical cord blood. Cognitive abilities were assessed as a part of a 6-year follow-up laboratory visit. Four subtests were given: reading, numbers, listening, and spatial ability. There were no significant differences between boys and girls in cognitive ability scores. Higher levels of perinatal androgens (testosterone and androstenedione) were significantly associated with low age-6 spatial ability in girls. Multiple regression analyses revealed a significant proportion of the variance in cognitive abilities in girls could be accounted for by testosterone and androstenedione. No significant predictions were found for boys. The finding of a stable inverse association between sex and effect of hormones on abilities is discussed.
Whether sex-steroid hormones are associated with cognitive abilities in boys and girls has been an intriguing question. There are both sex-related differences in cognitive abilities and in circulating sex-steroid hormones beginning in adolescence. However, when one tries to find a causal link, either in associations between hormonal measures and concurrent cognitive abilities or early hormonal and later cognitive abilities, the relationship is not clear.
Hormones may have the greatest effect early in fetal development when levels of the sex-steroid hormones are quite high (Faiman, Reyes, & Winter, 1974). The theoretical argument is that these sex-steroid hormones change the fetal brain even though behavioral effects may not be seen for years. The