Prenatal androgen influences on the brain: A review, critique, and illustration of research on congenital adrenal hyperplasia

Sex hormones, especially androgens, contribute to sex and gender differences in the brain and behavior. Organizational effects are particularly important because they are thought to be permanent, reflecting hormone exposure during sensitive periods of development. In human beings, they are often studied with natural experiments in which sex hormones are dissociated from other biopsychosocial aspects of development, such as genes and experiences. Indeed, the greatest evidence for organizational effects on sex differences in human behavior comes from studies of females with congenital adrenal hyperplasia (CAH), who have heightened prenatal androgen exposure, female-typical rearing, and masculinized toy play, activity and career interests, spatial skills, and some personal characteristics. Interestingly, however, neuroimaging studies of females with CAH have revealed few neural mechanisms underlying these hormone-behavior links, with the exception of emotion processing; studies have instead shown reduced gray matter volumes and reduced white matter integrity most consistent with other disease-related processes. The goals of this narrative review are to: (a) describe methods for studying prenatal androgen influences, while offering a brief overview of behavioral outcomes; (b) provide a critical methodological review of neuroimaging research on females with CAH; (c) present an illustrative analysis that overcomes methodological limitations of previous work, focusing on person-specific neural reward networks (and their associations with sensation seeking) in women with CAH and their unaffected sisters in order to inform future research questions and approaches that are most likely to reveal organizational hormone effects on brain structure and function.

Family environmental antecedents of pubertal timing in girls and boys: A review and open questions

Across nonhuman species, pubertal timing is affected by the social environment, with consequences for reproductive success and behavior. In human beings, variations in pubertal timing have not been systematically examined in relation to social environmental antecedents, although their psychological consequences are well documented. This paper focuses on links in human beings between pubertal timing and the childhood social environment, with several sections: A review of studies relating pubertal timing to the family context, a key aspect of the social environment; challenges in studying the issue; and opportunities for future work that takes advantage of and creates links with evidence in other species. The review shows that pubertal timing in girls is accelerated by adversity in aspects of the early family social context, with effects small in size; data in boys are not sufficient to enable conclusions. Inferences from existing studies are limited by variations in conceptualizations and measurement of relevant aspects of puberty and of the family social environment, and by methodological issues (e.g., reliance on existing data, use of retrospective reports, nonrandom missing data). Open questions remain about the nature, mechanisms, and specificity of the links between early family social environment and pubertal timing (e.g., form of associations, consideration of absence of positive experiences, role of timing of exposure). Animal studies provide a useful guide for addressing these questions, by delineating potential hormonal mechanisms that underlie links among social context, pubertal timing, and behavior, and encouraging attention to aspects of the social environment outside the family, especially peers.

Evidence and Implications from a Natural Experiment of Prenatal Androgen Effects on Gendered Behavior

Sex and gender are key to people's lives, and are the focus of scientific and popular interest and controversy. Sex-related psychological characteristics reflect more than socialization; they are influenced by sex hormones present during sensitive periods of development, particularly prenatal androgens. Studies of females with congenital adrenal hyperplasia (CAH) show how prenatal androgens affect behavior across the life span, with large effects on gendered activity interests and engagement, moderate effects on spatial abilities, and relatively small (or no) effects on gender identity, gender cognitions, and gendered peer involvement. In addition to showing the complexity of androgen effects on gendered behavior, studies of females with CAH provide an opportunity to test theories of gender development, understand how nature and nurture work together, and examine mechanisms of development. The implications of this work have often been misunderstood, so we consider what it means - and does not mean - for biology to influence gender-related behavior.

Consensus Parameter: Research Methodologies to Evaluate Neurodevelopmental Effects of Pubertal Suppression in Transgender Youth

Purpose: Pubertal suppression is standard of care for early pubertal transgender youth to prevent the development of undesired and distressing secondary sex characteristics incongruent with gender identity. Preliminary evidence suggests pubertal suppression improves mental health functioning. Given the widespread changes in brain and cognition that occur during puberty, a critical question is whether this treatment impacts neurodevelopment.

Methods: A Delphi consensus procedure engaged 24 international experts in neurodevelopment, gender development, puberty/adolescence, neuroendocrinology, and statistics/psychometrics to identify priority research methodologies to address the empirical question: is pubertal suppression treatment associated with real-world neurocognitive sequelae? Recommended study approaches reaching 80% consensus were included in the consensus parameter.

Results: The Delphi procedure identified 160 initial expert recommendations, 44 of which ultimately achieved consensus. Consensus study design elements include the following: a minimum of three measurement time points, pubertal staging at baseline, statistical modeling of sex in analyses, use of analytic approaches that account for heterogeneity, and use of multiple comparison groups to minimize the limitations of any one group. Consensus study comparison groups include untreated transgender youth matched on pubertal stage, cisgender (i.e., gender congruent) youth matched on pubertal stage, and an independent sample from a large-scale youth development database. The consensus domains for assessment includes: mental health, executive function/cognitive control, and social awareness/functioning.

Conclusion: An international interdisciplinary team of experts achieved consensus around primary methods and domains for assessing neurodevelopmental effects (i.e., benefits and/or difficulties) of pubertal suppression treatment in transgender youth.

Evidence needed to understand gender identity: Commentary on Turban & Ehrensaft (2018)

Turban and Ehrensaft (2018) have provided a thoughtful review of transgender identity in children and adolescents, emphasizing the benefits of the affirmative approach in maintaining positive psychological health in transgender individuals. The review reveals significant gaps in our understanding of gender identity regarding its nature, development, plasticity, causes, and links with other aspects of gender, and of the long-term benefits and costs of childhood social transitions. A full understanding of transgender identity requires studying cisgender identity too, and recognition that gender identity is continuous, develops across time and is not synonymous with gender expression or variations in gender-typed characteristics. Considerable evidence is needed before we can be confident that we are providing optimal treatment for children who are gender variant.

Gendered Peer Involvement in Girls with Congenital Adrenal Hyperplasia: Effects of Prenatal Androgens, Gendered Activities, and Gender Cognitions

A key question in understanding gender development concerns the origins of sex segregation. Children's tendencies to interact with same-sex others have been hypothesized to result from gender identity and cognitions, behavioral compatibility, and personal characteristics. We examined whether prenatal androgen exposure was related to time spent with boys and girls, and how that gendered peer involvement was related to sex-typed activities and gender identity and cognitions. We studied 54 girls with congenital adrenal hyperplasia (CAH) aged 10-13 years varying in degree of prenatal androgen exposure: 40 girls with classical CAH (C-CAH) exposed to high prenatal androgens and 14 girls with non-classical CAH (NC-CAH) exposed to low, female-typical, prenatal androgens. Home interviews and questionnaires provided assessments of gendered activity interests and participation, gender identity, and gender cognitions. Daily phone calls over 7 days assessed time spent in gendered activities and with peers. Girls with both C-CAH and NC-CAH interacted more with girls than with boys, with no significant group differences. The groups did not differ significantly in gender identity or gender cognitions, but girls with C-CAH spent more time in male-typed activities and less time in female-typed activities than did girls with NC-CAH. Time spent with girls reflected direct effects of gender identity/cognitions and gender-typed activities, and an indirect effect of prenatal androgens (CAH type) through gender-typed activities. Our results extend findings that prenatal androgens differentially affect gendered characteristics and that gendered peer interactions reflect combined effects of behavioral compatibility and feelings and cognitions about gender. The study also shows the value of natural experiments for testing hypotheses about gender development.

Beyond Pink and Blue: The Complexity of Early Androgen Effects on Gender Development

Why do girls and women differ from boys and men? Gender development is typically considered to result from socialization, but sex hormones present during sensitive periods of development, particularly prenatal androgens, play an important role. Data from natural experiments, especially from females with congenital adrenal hyperplasia, show the complexity of the effects of androgens on behavior: Prenatal androgens apparently have large effects on interests and engagement in gendered activities; moderate effects on spatial abilities; and relatively small or no effects on gender identity, gender cognitions, and gendered peer involvement. These differential effects provide an opportunity to move beyond identifying sources of variation in behavior to understanding developmental processes. These processes include links among gendered characteristics, psychological and neural mechanisms underlying development, and the joint effects of biological predispositions and social experiences.

Early Androgens Are Related to Childhood Sex-Typed Toy Preferences

Girls with congenital adrenal hyperplasia (CAH) who were exposed to high levels of androgen in the prenatal and early postnatal periods showed increased play with boys” toys and reduced play with girls' toys compared with their unexposed female relatives at ages 3 to 8. Boys with CAH did not differ from their male relatives in play with boys' or girls' toys. These results suggest that early hormone exposure in females has a masculinizing effect on sex-typed toy preferences.

Gender Assignment, Reassignment and Outcome in Disorders of Sex Development: Update of the 2005 Consensus Conference

BACKGROUND

Societal changes are increasingly moving the conceptualization of gender from a set of binary categories towards a bimodal continuum, which along with the cautious conclusions resulting from the 2005 Consensus Conference influences gender-related clinical work with patients with disorders of sex development.

OBJECTIVE

This article provides an update of these developments over the past decade along with an overview of pertinent new data.

CONCLUSION

Considerably more research is needed on larger sample sizes with systematic long-term follow-up to ground the emerging trends in clinical management of the highly diverse disorders of sex development syndromes in a solid empirical basis.

Linking Prenatal Androgens to Gender-Related Attitudes, Identity, and Activities: Evidence From Girls With Congenital Adrenal Hyperplasia

Key questions for developmentalists concern the origins of gender attitudes and their implications for behavior. We examined whether prenatal androgen exposure was related to gender attitudes, and whether and how the links between attitudes and gendered activity interest and participation were mediated by gender identity and moderated by hormones. Gender attitudes (i.e., gender-role attitudes and attitudes about being a girl), gender identity, and gender-typed activities were reported by 54 girls aged 10-13 years varying in degree of prenatal androgen exposure, including 40 girls with classical congenital adrenal hyperplasia (C-CAH) exposed to high prenatal androgens and 14 girls with non-classical (NC) CAH exposed to low, female-typical, prenatal androgens. Both girls with C-CAH and NC-CAH reported positive attitudes about being a girl and egalitarian gender attitudes, consistent with their female-typical gender identity. In contrast, girls with C-CAH had more male-typed activity interest and participation than girls with NC-CAH. Gender attitudes were linked to activities in both groups, with gender identity mediating the links. Specifically, gender-role attitudes and positive attitudes about being a girl were associated with feminine gender identity, which in turn was associated with decreased male-typed activity interests and participation, and increased female-typed activity interests. Our results are consistent with schema theories, with attitudes more closely associated with gender identity than with prenatal androgens.

Sex differences in resting state brain function of cigarette smokers and links to nicotine dependence

Sex--a marker of biological and social individual differences--matters for drug use, particularly for cigarette smoking, which is the leading cause of preventable death in the United States. More men than women smoke, but women are less likely than men to quit. Resting state brain function, or intrinsic brain activity that occurs in the absence of a goal-directed task, is important for understanding cigarette smoking, as it has been shown to differentiate between smokers and nonsmokers. But, it is unclear whether and how sex influences the link between resting state brain function and smoking behavior. In this study, the authors demonstrate that sex is indeed associated with resting state connectivity in cigarette smokers, and that sex moderates the link between resting state connectivity and self-reported nicotine dependence. Using functional MRI and behavioral data from 50 adult daily smokers (23 women), the authors found that women had greater connectivity than men within the default mode network, and that increased connectivity within the reward network was related to increased nicotine tolerance in women but to decreased nicotine tolerance in men. Findings highlight the importance of sex-related individual differences reflected in resting state connectivity for understanding the etiology and treatment of substance use problems.

Oral contraceptives and cognition: A role for ethinyl estradiol

This article is part of a Special Issue "Estradiol and cognition". Estrogens have been seen to play a role in human cognitive abilities, but questions remain about the cognitive impact of ethinyl estradiol, which is contained in many oral contraceptives (OCs). Inconsistencies in past studies likely reflect small samples and heterogeneous groups of OC users. The aims of the present work were to examine OC effects on sex-typed spatial and verbal abilities by (a) comparing mental rotations and expressional fluency in normally-cycling (NC) women and men to OC users considered as a heterogeneous group and then to homogeneous groups of OC users created by classifying pills according to their active constituents, and (b) determining the relation between synthetic hormone doses in OCs and mental rotations and expressional fluency. Participants were 136 men, 93 NC women, and 148 OC users, including homogeneous monophasic (n = 55) and triphasic (n = 43) OC groups, aged 18 to 30 years. Significant effects of OC use were seen in homogeneous group comparisons but not when OC users were considered as a heterogeneous group. On mental rotations, men outperformed women, and monophasic OC users outperformed NC women. The latter difference may be attributable to estradiol, as ethinyl estradiol was inversely related to spatial ability among OC users and was lower in monophasic than in triphasic users. On expressional fluency, NC women and monophasic OC users outperformed men, and monophasic users outperformed triphasic users. Thus, results show the importance of ethinyl estradiol and of considering pill constituents when studying the cognitive effects of OCs.

Genetic influences on pubertal development and links to behavior problems

Genetic influences on adolescent psychological development are likely to be mediated and moderated by pubertal hormones. Combining genetic analyses with advanced models of pubertal development, we extended work on the measurement and psychological significance of puberty. We examined how genetic and environmental influences on puberty vary by the way that development is described (logistic versus linear models versus traditional methods) and the different aspects of puberty (adrenarche vs. gonadarche), and how genes and environment contribute to the covariation between different descriptions and aspects of puberty, and between pubertal development and behavior problems (substance use, age at sexual initiation). We also considered how puberty moderated the heritability of psychological outcomes (internalizing and externalizing problems), and sex differences. Participants from the Colorado Longitudinal Twin Study (403 girls, 395 boys) reported their pubertal development annually from ages 9 through 15; they and their parents reported their behavior in mid-to-late adolescence. There was a large genetic contribution to pubertal timing for both sexes no matter how it was measured, but findings for pubertal tempo varied by method. Genetic covariation accounted for most of the phenotypic correlations among different indicators of pubertal timing, and between pubertal timing and psychological outcome. We consider the implications of our results for understanding how pubertal hormones mediate or moderate genetic and environmental influences on psychological development.

Gender development and sexuality in disorders of sex development

Understanding psychological development in individuals with disorders of sex development (DSD) is important for optimizing their clinical care and for identifying paths to competence and health in all individuals. In this paper, we focus on psychological outcomes likely to be influenced by processes of physical sexual differentiation that may be atypical in DSD, particularly characteristics related to being male or female (those that show sex differences in the general population, gender identity, and sexuality). We review evidence suggesting that (a) early androgens facilitate several aspects of male-typed behavior, with large effects on activity interests, and moderate effects on some social and personal behaviors (including sexual orientation) and spatial ability; (b) gender dysphoria and gender change occur more frequently in individuals with DSD than in the general population, with rates varying in relation to syndrome, initial gender assignment, and medical treatment; and (c) sexual behavior may be affected by DSD through several paths related to the condition and treatment, including reduced fertility, physical problems associated with genital ambiguity, social stigmatization, and hormonal variations. We also consider limitations to current work and challenges to studying gender and sexuality in DSD. We conclude with suggestions for a research agenda and a proposed research framework.

Psychological assessment of mothers and their daughters at the time of diagnosis of precocious puberty

Background

Concerns about psychological distress are often used to justify treatment of girls with precocious puberty, but there is little evidence to support these concerns. The extent to which psychological problems are associated with central precocious puberty (CPP) compared with other forms of early puberty in girls has likewise not been established.

Methods

Girls presenting with untreated CPP, premature adrenarche (PA) or early normal puberty (ENP) were recruited from our pediatric endocrine clinic along with their mothers. Child psychological adjustment was assessed by child self-report and parent report. Parent self-reported personality, anxiety, and depression were also assessed. Differences between groups were explored using one-way ANOVA and Dunnett’s T3 test.

Results

Sixty-two subjects (aged 7.5 ± 1.4 years, range 4.8-10.5) were enrolled, of whom 19 had CPP, 22 had PA, and 21 had ENP. Girls with ENP were significantly older (8.9 ± .9 years) than girls with CPP (6.9 ± 1.1 years, p < .001) and PA (6.6 ± 1.0 years, p < .001). Girls with PA had significantly higher BMI z-scores (1.7 ± .8) than girls with CPP (1.1 ± .6, p = .01) and ENP (1.2 ± .6, p = .04). More girls with PA and ENP were from racial minorities (47% and 50% respectively) than girls with CPP (32%). No group differences were found for any child measure of psychological adjustment. However, mothers of girls with PA scored significantly higher than mothers of girls with ENP on one measure of depression (p = .04) and stress (p = .01).

Conclusions

While mothers of girls with PA report increased psychological distress on some measures, no differences in psychological adjustment were found at baseline amongst the girls themselves. Whether these results will change as puberty progresses in the PA and ENP groups or with treatment of CPP is unknown. Long-term prospective studies are needed in order to further investigate psychological correlates of early puberty in girls.

The importance of puberty for adolescent development: conceptualization and measurement

How and why are teenagers different from children and adults? A key question concerns the ways in which pubertal development shapes psychological changes in adolescence directly through changes to the brain and indirectly through the social environment. Empirical work linking pubertal development to adolescent psychological function draws from several different perspectives, often with varying approaches and a focus on different outcomes and mechanisms. The main themes concern effects of atypical pubertal timing on behavior problems during adolescence, effects of pubertal status (and associated hormones) on normative changes in behaviors that can facilitate or hinder development (especially risk-taking, social reorientation, and stress responsivity), and the role of puberty in triggering psychopathology in vulnerable individuals. There is also interest in understanding the ways in which changes in the brain reflect pubertal processes and underlie psychological development in adolescence. In this chapter, we consider the ways that puberty might affect adolescent psychological development, and why this is of importance to developmentalists. We describe the processes of pubertal development; summarize what is known about pubertal influences on adolescent development; consider the assumptions that underlie most work and the methodological issues that affect the interpretation of results; and propose research directions to help understand paths from puberty to behavior. Throughout, we emphasize the importance of pubertal change in all aspects of psychological development, and the ways in which puberty represents an opportunity to study the interplay of biological and social influences.

Modeling pubertal timing and tempo and examining links to behavior problems

Research on the role of puberty in adolescent psychological development requires attention to the meaning and measurement of pubertal development. Particular questions concern the utility of self-report, the need for complex models to describe pubertal development, the psychological significance of pubertal timing vs. tempo, and sex differences in the nature and psychological significance of pubertal development. We used longitudinal self-report data to model linear and logistic trajectories of pubertal development, and used timing and tempo estimates from these models, and from traditional approaches (age at menarche and time from onset of breast development to menarche), to predict psychological outcomes of internalizing and externalizing behavior problems, and early sexual activity. Participants (738 girls, 781 boys) reported annually from ages 9 through 15 on their pubertal development, and they and their parents reported on their behavior in mid-to-late adolescence and early adulthood. Self-reports of pubertal development provided meaningful data for both boys and girls, producing good trajectories, and estimates of individuals' pubertal timing and tempo. A logistic model best fit the group data. Pubertal timing was estimated to be earlier in the logistic compared to linear model, but linear, logistic, and traditional estimates of pubertal timing correlated highly with each other and similarly with psychological outcomes. Pubertal tempo was not consistently estimated, and associations of tempo with timing and with behavior were model dependent. Advances in modeling facilitate the study of some questions about pubertal development, but assumptions of the models affect their utility in psychological studies.

Brain responses to sexual images in 46,XY women with complete androgen insensitivity syndrome are female-typical

Androgens, estrogens, and sex chromosomes are the major influences guiding sex differences in brain development, yet their relative roles and importance remain unclear. Individuals with complete androgen insensitivity syndrome (CAIS) offer a unique opportunity to address these issues. Although women with CAIS have a Y chromosome, testes, and produce male-typical levels of androgens, they lack functional androgen receptors preventing responding to their androgens. Thus, they develop a female physical phenotype, are reared as girls, and develop into women. Because sexually differentiated brain development in primates is determined primarily by androgens, but may be affected by sex chromosome complement, it is currently unknown whether brain structure and function in women with CAIS is more like that of women or men. In the first functional neuroimaging study of (46,XY) women with CAIS, typical (46,XX) women, and typical (46, XY) men, we found that men showed greater amygdala activation to sexual images than did either typical women or women with CAIS. Typical women and women with CAIS had highly similar patterns of brain activation, indicating that a Y chromosome is insufficient for male-typical human brain responses. Because women with CAIS produce male-typical or elevated levels of testosterone which is aromatized to estradiol these results rule out aromatization of testosterone to estradiol as a determinate of sex differences in patterns of brain activation to sexual images. We cannot, however, rule out an effect of social experience on the brain responses of women with CAIS as all were raised as girls.

Cognitive effects of variations in pubertal timing: is puberty a period of brain organization for human sex-typed cognition?

There is considerable interest in the organizational effects of pubertal sex hormones on human sex-related characteristics. Recent evidence from rodents suggests that there is a decreasing window of sensitivity to sex hormones throughout adolescence. If adolescence also represents a period of brain organization in human beings, then the timing of exposure to sex-typical hormones at puberty should have long-term effects on sex-typed characteristics: individuals with early timing should be more sex-typed than individuals with late timing. We tested this hypothesis in 320 young adults by relating their pubertal timing (retrospective comparison to peers) to cognitive abilities that show sex differences. Results provide partial support for the hypothesis. For men, pubertal timing was inversely related to scores on a test of three-dimensional mental rotations. Effects do not appear to be due to duration of hormone exposure (time since puberty), but other potential influences need further study.

Predictors and consequences of gender typicality: the mediating role of communality

Considerable work has shown the benefits for psychological health of being gender typed (i.e., perceiving oneself in ways that are consistent with one's sex). Nevertheless, little is known about the reasons for the link. In two studies of young adults (total N = 673), we studied (1) the ways in which gender typing is predicted from gender-related interests and personal qualities, and (2) links between gender typing and adjustment (self-esteem and negative emotionality). In the first study, gender typicality was positively predicted by a variety of gender-related characteristics and by communal traits, a female-typed characteristic; gender typicality was also positively associated with adjustment. To clarify the role of communality in predicting gender typicality and its link with adjustment, we conducted a follow-up study examining both gender typicality and "university typicality." Gender typicality was again predicted by gender-related characteristics and communality, and associated with adjustment. Further, university typicality was also predicted by communality and associated with adjustment. Mediation analyses showed that feelings of communality were partly responsible for the links between gender/university typicality and adjustment. Thus, the psychological benefits suggested to accrue from gender typicality may not be specific to gender, but rather may reflect the benefits of normativity in general. These findings were discussed in relation to the broader literature on the relation between identity and adjustment.

Changes in alcohol-related brain networks across the first year of college: a prospective pilot study using fMRI effective connectivity mapping

The upsurge in alcohol use that often occurs during the first year of college has been convincingly linked to a number of negative psychosocial consequences and may negatively affect brain development. In this longitudinal functional magnetic resonance imaging (fMRI) pilot study, we examined changes in neural responses to alcohol cues across the first year of college in a normative sample of late adolescents. Participants (N=11) were scanned three times across their first year of college (summer, first semester, second semester), while completing a go/no-go task in which images of alcoholic and non-alcoholic beverages were the response cues. A state-of-the-art effective connectivity mapping technique was used to capture spatiotemporal relations among brain regions of interest (ROIs) at the level of the group and the individual. Effective connections among ROIs implicated in cognitive control were greatest at the second assessment (when negative consequences of alcohol use increased), and effective connections among ROIs implicated in emotion processing were lower (and response times were slower) when participants were instructed to respond to alcohol cues compared to non-alcohol cues. These preliminary findings demonstrate the value of a prospective effective connectivity approach for understanding adolescent changes in alcohol-related neural processes.

Pubertal Timing as a Potential Mediator of Adoption Effects on Problem Behaviors

Adopted children show more problem behaviors than nonadopted children. Given that internationally-adopted individuals show earlier puberty than non-adopted individuals, and early puberty is associated with problem behaviors in nonadopted youth, we analyzed data from domestic adoptees to determine whether problem behaviors could be explained by differences in pubertal timing. Relative to nonadopted controls (n = 153), domestically-adopted girls (n = 121) had earlier menarche, earlier sexual initiation, and more conduct disorder symptoms. Age at menarche partially mediated the relation of adoptive status to sexual initiation, but not to conduct disorder symptoms. Extending findings from international adoptees, results show that domestic adoption is also linked to earlier puberty, and suggest early puberty as one mechanism linking adoption to problematic outcomes.

Early androgen effects on spatial and mechanical abilities: evidence from congenital adrenal hyperplasia

There is considerable controversy about the origins of sex differences in cognitive abilities, particularly the male superiority in spatial abilities. We studied effects of early androgens on spatial and mechanical abilities in adolescents and young adults with congenital adrenal hyperplasia (CAH). On tests of three-dimensional mental rotations, geography, and mechanical knowledge, females with CAH scored higher than their unaffected sisters, and males with CAH scored lower than their unaffected brothers. Exploratory regression analyses suggest that androgens affect spatial ability in females directly and through male-typed activity interests. Findings indicate that early androgens influence spatial and mechanical abilities, and that androgen effects on abilities may occur in part through effects on sex-typed activity interests.

Gendered occupational interests: prenatal androgen effects on psychological orientation to Things versus People

There is considerable interest in understanding women's underrepresentation in science, technology, engineering, and mathematics careers. Career choices have been shown to be driven in part by interests, and gender differences in those interests have generally been considered to result from socialization. We explored the contribution of sex hormones to career-related interests, in particular studying whether prenatal androgens affect interests through psychological orientation to Things versus People. We examined this question in individuals with congenital adrenal hyperplasia (CAH), who have atypical exposure to androgens early in development, and their unaffected siblings (total N=125 aged 9 to 26 years). Females with CAH had more interest in Things versus People than did unaffected females, and variations among females with CAH reflected variations in their degree of androgen exposure. Results provide strong support for hormonal influences on interest in occupations characterized by working with Things versus People.

The benefits and drawbacks of gender typing: how different dimensions are related to psychological adjustment

The benefits versus costs of gender typing are not clear: Is adjustment optimal when people identify and act in strongly gendered ways or when they embrace characteristics of both sexes? Previous findings are inconsistent, in part because they are derived from different conceptualizations of gender typing. A comprehensive understanding of the mental health consequences of gender typing requires recognition of the multidimensionality of gender typing and simultaneous consideration of these dimensions. On the basis of previous work on individual measures, we hypothesized that adjustment would be differentially associated with different aspects of gender typing: positively with sex-congruent gender identity and male-typed personality traits, negatively with rigid gender attitudes, and minimally with female-typed personality traits and gender-typed activity interests. Structural equation models were used to enable testing of all associations simultaneously. Results from a sample of 401 undergraduate students supported our hypotheses. For both women and men, adjustment was positively associated with gender-congruent identity, instrumentality, and flexible gender attitudes, and minimally related to activity interests and expressivity. These findings clarify the mental health benefits and costs of gender typing and highlight the multidimensionality of gender typing.

Fingers as a marker of prenatal androgen exposure

Interest in biological substrates of sex-related variations in psychological and physiological characteristics has led to a search for biomarkers of prenatal hormone exposure that can be measured postnatally. There has been particular interest in digit ratio, the relative lengths of the second and fourth fingers (2D:4D), but its validity as a measure of prenatal androgen has not been established. We report the strongest evaluation of the value of 2D:4D as a biomarker for early androgen exposure. Individuals with 46,XY karyotype but no effective prenatal androgen exposure due to complete androgen insensitivity syndrome had digit ratios that were feminized: they were higher than those of typical men and similar to those of typical women. Nevertheless, the effect was modest in size, and there was considerable within-group variability and between-group overlap, indicating that digit ratio is not a good marker of individual differences in prenatal androgen exposure.

Prenatal sex hormone effects on child and adult sex-typed behavior: methods and findings

There is now good evidence that human sex-typed behavior is influenced by sex hormones that are present during prenatal development, confirming studies in other mammalian species. Most of the evidence comes from clinical populations, in which prenatal hormone exposure is atypical for a person's sex, but there is increasing evidence from the normal population for the importance of prenatal hormones. In this paper, we briefly review the evidence, focusing attention on the methods used to study behavioral effects of prenatal hormones. We discuss the promises and pitfalls of various types of studies, including those using clinical populations (concentrating on those most commonly studied, congenital adrenal hyperplasia, androgen insensitivity syndrome, ablatio penis, and cloacal exstrophy), direct measures of hormones in the general population (assayed through umbilical cord blood, amniotic fluid, and maternal serum during pregnancy), and indirect measures of hormones in the general population (inferred from intrauterine position and biomarkers such as otoacoustic emissions, finger length ratios, and dermatoglyphic asymmetries). We conclude with suggestions for interpreting and conducting studies of the behavioral effects of prenatal hormones.

Psychological adjustment in children and adults with congenital adrenal hyperplasia

OBJECTIVE

To determine psychological health in individuals with one form of intersexuality, congenital adrenal hyperplasia (CAH), and its relation to characteristics of the disease and treatment.

STUDY DESIGN

Participants (ages 3-31 years) included 72 females and 42 males with CAH, and unaffected relatives (44 females and 69 males). Psychological adjustment was assessed with parent-reports on the Child Behavior Checklist (CBCL) and subject self-reports on the Self-Image Questionnaire for Young Adolescents (SIQYA) or the Multidimensional Personality Questionnaire (MPQ). Information about disease characteristics and genital surgery was obtained from medical records.

RESULTS

There were no significant differences between females with CAH and unaffected females on any measure. Psychological adjustment was not significantly associated with genital virilization or age at genital surgery. Males with CAH were not significantly different from unaffected males in childhood, but they showed more negative affect at older ages.

CONCLUSIONS

Psychological adjustment is not compromised in females with virilized genitalia who are treated early in life and reared as females. Adjustment does not appear to depend on the characteristics of the disease or its treatment, but sample size and restricted range limit generalizability about adjustment-disease associations.

Effects on gender identity of prenatal androgens and genital appearance: evidence from girls with congenital adrenal hyperplasia

To address questions about sex assignment in children with ambiguous genitalia, we studied gender identity in girls with congenital adrenal hyperplasia (CAH) in relation to characteristics of the disease and treatment, particularly genital appearance and surgery. A 9-item gender identity interview was administered to 43 girls with classical CAH ranging in age from 3-18 yr, 7 tomboys, and 29 sister control girls. Groups were compared on total score and on individual items. Results showed that, on the total gender identity score, 88% of girls with CAH had scores overlapping those of control girls, but the average score was intermediate between control girls and tomboys. On individual items of gender identity (discomfort as a girl, wish to be a boy), girls with CAH were similar to control girls. Gender identity in girls with CAH was not related to degree of genital virilization or age at which genital reconstructive surgery was done. Thus, moderate androgen excess early in development appears to produce a small increase in the risk of atypical gender identity, but this risk cannot be predicted from genital virilization.

Who are tomboys and why should we study them?

Tomboys are girls who behave like boys and, as such, challenge some theories of sex-typing. We recruited tomboys (N = 60) ages 4-9 through the media and compared them with their sisters (N = 15) and brothers (N = 20) on measures of playmate preference, sex-typed activities and interests, and gender identity. On nearly all measures, tomboys were substantially and significantly more masculine than their sisters, but they were generally less masculine than their brothers. We outline some scientific benefits of studying tomboys and describe some goals and initial findings of the Tomboy Project.

Cognitive function in congenital adrenal hyperplasia

Cognition in patients with CAH has not been as well studied as other aspects of psychologic function. Nevertheless, it is possible to make some conclusions and to offer a number of hypotheses for further study (Table 1). First, patients with CAH do not seem to have an overall intellectual advantage as a direct consequence of the disease. The high IQs reported in some groups of patients with CAH are also reported in their siblings and probably reflect sampling bias. Second, it is possible that, on average, patients with salt-wasting CAH have lower overall ability than patients with the simple-virilizing form, but both groups are well within the normal range, and there is considerable variability among both groups. Third, the evidence to date does not confirm that patients with CAH are more likely to have diagnosable learning disabilities when compared with their unaffected relatives, but this issue has not been well studied with the appropriate psychoeducational assessments. It is unlikely that patients with CAH are at substantially increased risk for frank learning disabilities, but they may be likely to have problems in specific areas. Fourth, females with CAH seem to have enhanced spatial ability as a result of exposure to high levels of androgens early in development. The neural substrate of this advantage is unknown but a subject of active research. It is unclear whether when compared with their unaffected siblings, females with CAH are better in other abilities that are typically performed best by males or worse in abilities typically performed best by females. Fifth, it is likely that patients with CAH have other cognitive changes as a consequence of disease characteristics (besides androgens) and of the treatment of the disease. Some evidence suggests that patients with CAH are more likely to have white-matter brain changes produced by the disease and its treatment. This has not been well studied but should be because of the potential clinical implications. It is reasonable to hypothesize that there will be cognitive changes that reflect effects of undertreatment (e.g., ACTH effects on attention) and other changes that reflect effects of overtreatment (e.g., glucocorticoid effects on memory). Some of these effects may be transient, reflecting acute brain changes, whereas others may become chronic as a result of permanent brain changes with repeated exposure. There is need for continuing study of cognition in patients with CAH. Such studies will provide basic information about hormonal effects on cognition and the neural mechanisms that mediate those effects. They will also provide important clinical information to guide psychologic and medical treatment of patients.

Behavioral effects of prenatal versus postnatal androgen excess in children with 21-hydroxylase-deficient congenital adrenal hyperplasia

Systematic behavioral studies show that females with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH) are masculinized and defeminized in several ways; compared to their sisters, they play more with boys' toys, are more likely to use aggression when provoked, and show less interest in infants. We studied the extent to which these behavioral changes could be attributed to high levels of androgens in the prenatal vs. postnatal periods in 23 girls with CAH, aged 3-12 yr. Sex-atypical behavior was significantly associated with degree of inferred prenatal, but not postnatal, androgen excess; marked boy-typical play was associated with severe salt-wasting CAH, early age at diagnosis, and moderate genital masculinization at birth, but not with bone age advance, concurrent or cumulative high levels of 17-hydroxyprogesterone, or accelerated growth velocity in early childhood. Aggression and interest in infants were not consistently associated with indicators of prenatal or postnatal androgen excess, probably because those behaviors were measured less reliably than was toy play. The results are consistent with the idea that behavioral masculinization in girls with CAH results from high levels of androgens during fetal development and not in postnatal life.

Neuropsychological follow-up in neonatal screening: issues, methods and findings

There are several ongoing studies of psychological outcome in children identified through neonatal screening with phenylketonuria, congenital hypothyroidism or congenital adrenal hyperplasia. These studies document the reduction in mental retardation, learning difficulties and behaviour problems associated with neonatal screening. They also describe other behavioural changes resulting from these disorders. Some behavioural changes are transient or preventable with early diagnosis and treatment, whereas some appear to be irreversible, reflecting permanent brain effects of abnormalities associated with the disease. Despite the variety of disorders studied, there are commonalities in approach and issues, including a developmental neuropsychological perspective resulting in behavioural assessments specific to the disorder and its likely manifestations, a recognition that behaviour may change across time in association with brain development and an understanding of the neural mechanisms underlying the behavioural changes. Assessments go beyond IQ, and include specific intellectual abilities, social behaviour, temperament, behaviour problems and identity. Behavioural changes are related to specific characteristics of the disease and its treatment, including the timing of exposure to abnormal hormones and/or neurotransmitters, the severity of the disease, and the age at initiation and adequacy of treatment. These studies provide information about the ways in which hormones and neurotransmitters affect the development and ongoing function of the brain, and an understanding of the ways in which neonatal screening results in improved psychological outcome. They also provide models for psychological follow-up of other disorders detected through neonatal screening.

Effects of early androgens on sex-typed activities and interests in adolescents with congenital adrenal hyperplasia

The goal of this study was to examine the relation of early androgen exposure to sex-typed activities and interests in adolescence. Participants aged 9-19 years included 24 girls and 18 boys with congenital adrenal hyperplasia (CAH) and 16 unaffected sisters and 24 unaffected brothers who served as controls. Using standardized questionnaires, adolescents reported on their participation in sex-typed activities and interest in sex-typed occupations, and parents reported on the adolescents' activities. As hypothesized, girls with CAH showed sex-atypical preferences: increased interest in male-typical activities and careers and reduced interest in female-typical activities and careers compared to the unexposed control girls. These results extend findings of sex-atypical play in young girls with CAH and suggest that the sex-atypical activities and interests of females with CAH reflect direct effects of androgens on the developing brain rather than social responses to virilized genitalia. These results also suggest that population sex differences in activities and interests arise in part from sex differences in early androgens.

Results of screening 1.9 million Texas newborns for 21-hydroxylase-deficient congenital adrenal hyperplasia

OBJECTIVE

To assess results of newborn screening for 21-hydroxylase-deficient congenital adrenal hyperplasia (CAH) in Texas over 6 years of screening 1.9 million infants.

METHODS

In 1989, CAH was incorporated into the ongoing Texas Newborn Screening Program, which requires two screens on each newborn. 17-Hydroxyprogesterone was assayed, without extraction, by radioimmunoassay of blood collected from heel sticks onto filter paper collection cards. Infants with elevated levels of 17-hydroxyprogesterone were referred for evaluation, and those considered to have CAH were studied with respect to disease characteristics. Data were collected by pediatric endocrinologists using standardized forms that included type of CAH, results of laboratory tests, treatment regimen, disease symptoms and signs, and, for girls, degree of genital virilization.

RESULTS

The incidence of classic CAH in Texas is 1:16 008, with a ratio of salt-wasting to simple-virilizing of 2.7:1. A majority of infants detected were undiagnosed until screened, despite signs of salt-wasting or ambiguous genitalia. It was difficult to differentiate salt-wasting from simple-virilizing CAH in infants who were identified before the onset of adrenal insufficiency or electrolyte abnormalities. A substantial number of infants with nonclassic (NC) CAH also were detected. Not all infants were detected on the initial screen; 14% of infants with classic CAH and 87% with NC CAH were detected on the second routine screening test.

CONCLUSIONS

Our findings confirm the benefits of newborn screening for CAH and the importance of a second screening test, and suggest that programs for newborn CAH screening must consider complex issues in diagnosis and treatment. These results also confirm that CAH is a continuum of disorders, rather than a disorder with discrete subtypes. In addition, the difficulties in differentiating CAH subtypes in newborns, and thus deciding appropriate treatment, and the high incidence of NC CAH suggest that standard diagnostic criteria and treatment regimens for CAH may need modification. Where screening exists, physicians will encounter more cases of CAH than in the past.

Sex differences in right hemisphere tasks

We tested the hypothesis that sex differences in spatial ability and emotional perception are due to sex differences in intrahemispheric organization of the right hemisphere. If the right hemisphere is differently organized by sex-primarily specialized for spatial ability in men, but primarily specialized for emotional perception in women-then there should be a negative correlation between spatial ability and emotional perception within sex, and the greatest disparity between abilities should be found in people with characteristic arousal of the right hemisphere. Undergraduate men (N = 86) and women (N = 132) completed tests of Mental Rotation, Surface Development, Profile of Nonverbal Sensitivity, Progressive Matrices, and Chimeric Faces. Although the expected pattern of sex differences was observed, there was no evidence for the hypothesized negative correlation between spatial ability and emotional perception, even after statistical control of general intelligence.

Role of the hippocampus in sex differences in verbal memory: memory outcome following left anterior temporal lobectomy

The authors examined the neural and cognitive bases for sex differences in verbal memory in 57 patients who underwent left anterior temporal lobectomy (ATL) for the treatment of intractable seizures. On the California Verbal Learning Test (D. C. Delis, J. H. Kramer, E. Kaplan, & B. A. Ober, 1987), women recalled more words than men both before and after surgery, regardless of the extent of hippocampal damage. Extent of hippocampal sclerosis was related to memory loss in both men and women. Women's superiority in verbal memory appears to result in part from their use of an efficient encoding strategy. Women were more likely than men to use semantic clustering both before and after ATL, and sex differences in word recall were attenuated after scores were adjusted for semantic clustering. There was no effect of ATL on semantic clustering. Taken together, these results suggest that sex differences in verbal memory are not due to differences in the integrity of the left hippocampus.

Early androgen effects on aggression in children and adults with congenital adrenal hyperplasia

Males are more likely than females to show aggressive behavior across species, ages, and situations, and these differences may be partly influenced by early hormones. We studied aggression in three samples of subjects with congenital adrenal hyperplasia (CAH), who were exposed to high levels of androgen in the prenatal and early postnatal periods. Controls were siblings and first cousins similar in age. In Sample 1, adolescents and adults completed the Multidimensional Personality Questionnaire (MPQ), which includes an Aggression scale. In Sample 2, adolescents and adults completed the MPQ and a paper-and-pencil version of Reinisch's Aggression Inventory. In Sample 3, parents rated the aggression of children aged 3-12, using a modification of Reinisch's Inventory. In all three samples, control males had higher aggression scores than control females. Further, as predicted, females with CAH had higher aggression than control females, but the difference was significant only in adolescents and adults. These results suggest that early androgens contribute to variability in human aggression.

Role of the hippocampus in sex differences in verbal memory: memory outcome following left anterior temporal lobectomy

The authors examined the neural and cognitive bases for sex differences in verbal memory in 57 patients who underwent left anterior temporal lobectomy (ATL) for the treatment of intractable seizures. On the California Verbal Learning Test (D. C. Delis, J. H. Kramer, E. Kaplan, & B. A. Ober, 1987), women recalled more words than men both before and after surgery, regardless of the extent of hippocampal damage. Extent of hippocampal sclerosis was related to memory loss in both men and women. Women's superiority in verbal memory appears to result in part from their use of an efficient encoding strategy. Women were more likely than men to use semantic clustering both before and after ATL, and sex differences in word recall were attenuated after scores were adjusted for semantic clustering. There was no effect of ATL on semantic clustering. Taken together, these results suggest that sex differences in verbal memory are not due to differences in the integrity of the left hippocampus.

Sex-typed play in opposite-sex twins

To examine possible prenatal hormonal influences on sex-typed play, we compared girls with a boy co-twin to girls with a girl co-twin and girls with an older brother. In opposite-sex dizygotic twin pairs, the uterine environment may allow transfer of testosterone from the male to the female fetus. Singletons with an older brother provide a control for shared social environment. Girls aged 3 to 8 years (N = 91) were observed playing with sex-typed toys, and mothers completed questionnaires about the child's activities. Contrary to expectation, girls with a boy co-twin did not spend more time playing with boys' toys than girls with a girl co-twin or girls with an older brother. Although these results might suggest that normal variations in hormones do not contribute to within-sex variations in childhood activities, they combine with other work to suggest factors to consider in evaluating hormonal influences on human behavior, including level and timing of exposure.

Evaluating the empirical support for the role of testosterone in the Geschwind-Behan-Galaburda model of cerebral lateralization: commentary on Bryden, McManus, and Bulman-Fleming

The main tenet of the GBG model relates to the prenatal action of testosterone. Anomalies in cerebral dominance, immune functioning, abilities, and neural crest development are hypothesized to correlate with each other because all result from high levels of prenatal testosterone. Studies directly evaluating the effect of testosterone on these traits do not validate the model: sex ratios and animal studies suggest that testosterone has a protective, rather than facilitatory, effect on autoimmune diseases; individuals with high levels of early testosterone do not have elevated rates of left-handedness or learning disabilities. These findings reinforce Bryden et al.'s conclusions that there is little empirical support for the GBG model, and that it is wise to consider other theories in evaluating data derived from the model.