Early individual differences in prosocial behaviors

During early development, testosterone plays an important role in sexual differentiation of the mammalian brain and has enduring influences on behavior. Testosterone exerts these influences at times when the testes are active, as evidenced by higher concentrations of testosterone in developing male than in developing female animals. This article critically reviews the available evidence regarding influences of testosterone on human gender-related development. In humans, testosterone is elevated in males from about weeks 8 to 24 of gestation and then again during early postnatal development. Individuals exposed to atypical concentrations of testosterone or other androgenic hormones prenatally, for example, because of genetic conditions or because their mothers were prescribed hormones during pregnancy, have been consistently found to show increased male-typical juvenile play behavior, alterations in sexual orientation and gender identity (the sense of self as male or female), and increased tendencies to engage in physically aggressive behavior. Studies of other behavioral outcomes following dramatic androgen abnormality prenatally are either too small in their numbers or too inconsistent in their results, to provide similarly conclusive evidence. Studies relating normal variability in testosterone prenatally to subsequent gender-related behavior have produced largely inconsistent results or have yet to be independently replicated. For studies of prenatal exposures in typically developing individuals, testosterone has been measured in single samples of maternal blood or amniotic fluid. These techniques may not be sufficiently powerful to consistently detect influences of testosterone on behavior, particularly in the relatively small samples that have generally been studied. The postnatal surge in testosterone in male infants, sometimes called mini-puberty, may provide a more accessible opportunity for measuring early androgen exposure during typical development. This approach has recently begun to be used, with some promising results relating testosterone during the first few months of postnatal life to later gender-typical play behavior. In replicating and extending these findings, it may be important to assess testosterone when it is maximal (months 1 to 2 postnatal) and to take advantage of the increased reliability afforded by repeated sampling.

While reports showing a link between prenatal androgen exposure and human gender role behavior are consistent and the effects are robust, associations to gender identity or cross-gender identification are less clear. The aim of the current study was to investigate potential cross-gender identification in girls exposed prenatally to high concentrations of androgens due to classical congenital adrenal hyperplasia (CAH). Assessment included two standardized measures and a short parent interview assessing frequency of behavioral features of cross-gender identification as conceptualized in Part A of the diagnostic criteria for gender identity disorder (GID) in the DSM-IV-TR. Next, because existing measures may have conflated gender role behavior with gender identity and because the distinction is potentially informative, we factor analyzed items from the measures which included both gender identity and gender role items to establish the independence of the two constructs. Participants were 43 girls and 38 boys with CAH and 41 unaffected female and 31 unaffected male relatives, aged 4- to 11-years. Girls with CAH had more cross-gender responses than female controls on all three measures of cross-gender identification as well as on a composite measure of gender identity independent of gender role behavior. Furthermore, parent report indicated that 5/39 (12.8 %) of the girls with CAH exhibited cross-gender behavior in all five behavioral domains which comprise the cross-gender identification component of GID compared to 0/105 (0.0 %) of the children in the other three groups combined. These data suggest that girls exposed to high concentrations of androgens prenatally are more likely to show cross-gender identification than girls without CAH or boys with and without CAH. Our findings suggest that prenatal androgen exposure could play a role in gender identity development in healthy children, and may be relevant to gender assignment in cases of prenatal hormone disruption, including, in particular, cases of severely virilized 46, XX CAH.

Background: There is a marked male preponderance in autism spectrum conditions. The extreme male brain theory and the fetal androgen theory of autism suggest that elevated prenatal testosterone exposure is a key contributor to autistic traits. The current paper reports findings from two separate studies that test this hypothesis. Methods: A parent-report questionnaire, the Childhood Autism Spectrum Test (CAST), was employed to measure autistic traits in both studies. The first study examined autistic traits in young children with congenital adrenal hyperplasia (CAH), a condition causing unusually high concentrations of testosterone prenatally in girls. 81 children with CAH (43 girls) and 72 unaffected relatives (41 girls), aged 4 to 11 years, were assessed. The second study examined autistic traits in relation to amniotic testosterone in 92 typically-developing children (48 girls), aged 3 to 5 years. Results: Findings from neither study supported the association between prenatal androgen (testosterone) exposure and autistic traits. Specifically, young girls with and without CAH did not differ significantly in CAST scores and amniotic testosterone concentrations were not significantly associated with CAST scores in boys, girls, or the whole sample. Conclusions: These studies do not support a relationship between prenatal testosterone exposure and autistic traits. These findings augment prior research suggesting no consistent relationship between early androgen exposure and autistic traits.

Individuals with classic congenital adrenal hyperplasia (CAH) experience impaired glucocorticoid production and are treated postnatally with glucocorticoids. Prior research with animals and other human populations indicates that glucocorticoids can influence memory, particularly working memory. We tested the hypothesis that children with CAH would show reduced working memory. Children in the United Kingdom, aged 7-11 years, with classical CAH (31 girls, 26 boys) were compared to their unaffected relatives (30 girls, 20 boys) on a test of working memory, the Digit Span test. Vocabulary was also assessed to measure verbal intelligence for control purposes. Children with CAH showed reduced working memory performance compared to controls, on both components of the Digit Span test: p = .008 for Digit Span Forward, and p = .027 for Digit Span Backward, and on a composite score, p = .004. These differences were of moderate size (d = .53 to .70). Similar differences were also seen in a subset of 23 matched pairs of children with CAH and their relatives (d = .78 to .92). There were no group differences on Vocabulary. Glucocorticoid abnormality, including treatment effects, could be responsible for the reduced Digit Span performance in children with CAH. Other factors related to CAH, such as salt-wasting crises, could also be involved. Additional research is needed to identify the cause of the memory reduction, which will help to determine if more rapid diagnosis or more precise glucocorticoid treatment would help prevent memory reduction. Educational interventions might also be considered for children with CAH.