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.     

Prenatal hormones and childhood sex segregation: playmate and play style preferences in girls with congenital adrenal hyperplasia

We investigated playmate and play style preference in children with congenital adrenal hyperplasia (CAH) (26 females, 31 males) and their unaffected siblings (26 females, 17 males) using the Playmate and Play Style Preferences Structured Interview (PPPSI). Both unaffected boys and girls preferred same-sex playmates and sex-typical play styles. In the conflict condition where children chose between a same-sex playmate engaged in an other-sex activity or an other-sex playmate engaged in a same-sex activity, boys (both CAH and unaffected brothers) almost exclusively chose playmates based on the preferred play style of the playmate as opposed to the preferred gender label of the playmate. By contrast, unaffected girls used play style and gender label about equally when choosing playmates. Girls with CAH showed a pattern similar to that of boys: their playmate selections were more masculine than unaffected girls, they preferred a boy-typical play style and, in the conflict condition, chose playmates engaged in a masculine activity. These findings suggest that prenatal androgen exposure contributes to sex differences in playmate selection observed in typically developing children and that, among boys and girls exposed to high levels of androgens prenatally, play style preferences drive sex segregation in play.     

Personality and congenital adrenal hyperplasia: Possible effects of prenatal androgen exposure

Influences of early androgen exposure on personality were investigated. Participants were either exposed to abnormal levels of androgens prenatally due to congenital adrenal hyperplasia (CAH, 40 females, 29 males), or were unaffected relative controls (29 females, 30 males). Compared to female controls, females with CAH were less tender-minded (p < .001; 16 Personality Factor Inventory (16PF)), and reported greater physical aggression (p = .03; Reinisch Aggression Inventory) and less interest in infants (p < .001; Melson's Questionnaire), but did not differ in dominance (16PF). Males with CAH did not differ from male controls in interest in infants but were less dominant (p = .008), and more tender-minded (p = .033) and reported reduced physical aggression (p = .025). Thus, both males and females with CAH showed alteration in three of the four constructs assessed. Prenatal androgen exposure may shift some, but not all, personality characteristics in the male-typical direction in females. It may also be associated with a decrease in some aspects of male-typical personality development in males, although personality differences in males with CAH could relate to illness.     

Masculinized finger length patterns in human males and females with congenital adrenal hyperplasia

The ratio of the length of the second digit (2D) to the length of the fourth digit (4D) is greater in women than in men. Since androgens are involved in most somatic sex differences and since the sexual dimorphism in 2D:4D is stable from 2 years of age in humans, it was hypothesized that finger length pattern development might be affected by early androgen exposure. Human females with congenital adrenal hyperplasia (CAH) are exposed prenatally to higher than normal levels of adrenal androgens, providing an opportunity to test the effects of early androgen exposure on digit ratios. The 2D:4D was calculated for females with CAH, females without CAH, males with CAH, and males without CAH. Females with CAH had a significantly smaller 2D:4D on the right hand than did females without CAH. Males with CAH had a significantly smaller 2D:4D on the left hand than did males without CAH. A subset of six males with CAH had a significantly smaller 2D:4D on both hands compared with their male relatives without CAH. These results are consistent with the idea that prenatal androgen exposure reduces the 2D:4D and plays a role in the establishment of the sex difference in human finger length patterns. Finger lengths may therefore offer a retrospective marker of perinatal androgen exposure in humans.     

Increased aggression and activity level in 3- to 11-year-old girls with congenital adrenal hyperplasia (CAH)

Experimental research in a wide range of mammals has documented powerful influences of androgen during early development on brain systems and behaviors that show sex differences. Clinical research in humans suggests similar influences of early androgen concentrations on some behaviors, including childhood play behavior and adult sexual orientation. However, findings have been inconsistent for some other behaviors that show sex differences, including aggression and activity level in children. This inconsistency may reflect small sample sizes and assessment limitations. In the present study, we assessed aggression and activity level in 3- to 11-year-old children with CAH (38 girls, 29 boys) and in their unaffected siblings (25 girls, 21 boys) using a questionnaire that mothers completed to indicate current aggressive behavior and activity level in their children. Data supported the hypotheses that: (1) unaffected boys are more aggressive and active than unaffected girls; (2) girls with CAH are more aggressive and active than their unaffected sisters; and (3) boys with and without CAH are similar to one another in aggression and activity level. These data suggest that early androgens have a masculinizing effect on both aggressive behavior and activity level in girls.     

Ectoparasite-modulated deposition of maternal androgens in great tit eggs

Maternal yolk androgens can promote growth and competitive abilities of nestling birds but are also suggested to increase susceptibility to parasites or suppress immune function. We tested the hypothesis that females exposed to ectoparasites during egg formation will adjust the content of androgens in the yolk. We predicted that when anticipating high levels of parasitism, females deposit (i) less androgens into all eggs of their clutch and (ii) smaller amounts of androgens in eggs late in the laying sequence to facilitate brood reduction. In a field experiment we exposed female great tits (Parus major) to hen fleas (Ceratophyllus gallinae), or kept them free of ectoparasites prior to egg laying. We collected the eggs and measured yolk concentrations of androstenedione (A4), testosterone (T) and 5alpha-dihydrotestosterone (DHT) by radioimmunoassay. Among clutches, eggs of ectoparasite-exposed females contained significantly less A4 and tended to contain less T, whereas DHT content was unaffected. Within clutches, content of A4 and T increased significantly with laying order whereas DHT content significantly decreased. These patterns were unaffected by ectoparasites. In summary, our results provide no evidence for hormone-based facilitation of brood reduction under ectoparasite exposure but support the hypothesis that females exposed to ectoparasites reduce levels of T and its precursor A4 in yolk and might thereby reduce the negative effects of parasites on offspring.     

Androgens and autistic traits: A study of individuals with congenital adrenal hyperplasia

Testosterone promotes male-typical neural and behavioral development in non-human mammals. There is growing evidence that testosterone exerts similar influences on human development, although the range of behaviors affected is not completely known. This study examined the hypothesis that autistic traits are increased following prenatal exposure to abnormally high levels of testosterone caused by congenital adrenal hyperplasia (CAH). Sixty individuals with CAH (34 female, 26 male) and 49 unaffected relatives (24 female, 25 male) completed the Autism Spectrum Quotient (AQ). Females with CAH scored significantly higher than unaffected females on total AQ score, largely due to enhanced scores on subscales measuring social skills and imagination. These results suggest that prenatal exposure to high levels of testosterone influences some autistic traits and that hormonal factors may be involved in vulnerability to autism.     

Cognitive outcome in adult women affected by congenital adrenal hyperplasia due to 21-hydroxylase deficiency

BACKGROUND: Some research suggests that girls with congenital adrenal hyperplasia (CAH), who are exposed to higher than normal levels of prenatal androgens, perform better on spatial tasks, worse on verbal tasks and have a greater incidence of left-handedness than unaffected controls, all of which suggests the development of a more male-typical cognitive pattern. However, research in all three areas has produced inconsistent findings. OBJECTIVES: To determine if prenatal androgen exposure has an organizing effect on female cognitive development and to what extent. METHODS: 24 women, 21-71 years, with either the salt-losing (SL) or simple virilizing (SV) forms of CAH due to 21-hydroxylase deficiency, and 18 controls, 21-73 years, who were unaffected female relatives or women with polycystic ovary syndrome, were assessed with IQ, handedness, executive function, verbal learning and memory, non-verbal learning and memory, perceptual speed, visuospatial processing and visuomotor ability measures. The battery included tests known to elicit sex differences and control measures. RESULTS: The findings did not support the hypothesis that women with CAH develop a more male-typical cognitive pattern. CONCLUSION: This study differs from others in the older age of its participants, grouping by SL/SV diagnosis and assessment of medical treatment and compliance as determined through hormone assays. Our findings provide additional support for the conclusion that, in adult women with CAH, previous prenatal androgen exposure does not enhance spatial abilities, impair verbal abilities nor alter hand preferences in a long-lasting way.     

Psychosexual Development of Women with Congenital Adrenal Hyperplasia

Women with congenital adrenal hyperplasia (CAH) (N= 31) and their unaffected sisters or female cousins (N= 15) participated in a study of psychosexual development. All participants were ≥18 years of age (mean age, 25 years; range, 18–40). Comparisons were also made between the CAH women with the salt-wasting (SW) form of the disorder and those with simple virilization (SV). A psychosexual assessment protocol examined six variables: (1) sex assignment at birth (probands only); (2) recalled sex-typed behavior during childhood; (3) gender identity and gender role identification in adulthood; (4) relationship status; (5) sexual orientation in fantasy; and (6) sexual orientation in behavior. Salt-wasting status and sex assignment at birth were also ascertained for the CAH women who either refused to participate in the study (N= 10) or could not be traced (N= 13). Compared to the controls, the women with CAH recalled more cross-gender role behavior and less comfort with their sense of “femininity” during childhood. The two groups did not differ in degree of gender dysphoria in adulthood, although the probands showed more cross-gender role identification. Three of the nonparticipant probands were living, as adults, in the male social role (2 reared from birth as boys and 1 who changed from the female to the male social role during adolescence). The CAH women and the controls did not differ in relationship status (married/cohabiting vs. single). The CAH women had lower rates of exclusive heterosexual fantasy and fewer sexual experiences with men than the controls; however, the CAH women did not have more sexual experiences with women than the controls. Comparisons between the SW and SV revealed several differences: the SW were less likely to be assigned to the female sex at birth, recalled more cross-gender role behavior during childhood, were less likely to be married or cohabiting, and had lower rates of sexual experiences with men. The results were discussed in relation to the effects of prenatal androgens on psychosexual differentiation.     

Otoacoustic emissions,auditory evoked potentials and self-reported gender in people affected by disorders of sex development (DSD)

Both otoacoustic emissions (OAEs) and auditory evoked potentials (AEPs) are sexually dimorphic, and both are believed to be influenced by prenatal androgen exposure. OAEs and AEPs were collected from people affected by 1 of 3 categories of disorders of sex development (DSD) — (1) women with complete androgen insensitivity syndrome (CAIS); (2) women with congenital adrenal hyperplasia (CAH); and (3) individuals with 46,XY DSD including prenatal androgen exposure who developed a male gender despite initial rearing as females (men with DSD). Gender identity (GI) and role (GR) were measured both retrospectively and at the time of study participation, using standardized questionnaires. The main objective of this study was to determine if patterns of OAEs and AEPs correlate with gender in people affected by DSD and in controls. A second objective was to assess if OAE and AEP patterns differed according to degrees of prenatal androgen exposure across groups. Control males, men with DSD, and women with CAH produced fewer spontaneous OAEs (SOAEs) – the male-typical pattern – than control females and women with CAIS. Additionally, the number of SOAEs produced correlated with gender development across all groups tested. Although some sex differences in AEPs were observed between control males and females, AEP measures did not correlate with gender development, nor did they vary according to degrees of prenatal androgen exposure, among people with DSD. Thus, OAEs, but not AEPs, may prove useful as bioassays for assessing early brain exposure to androgens and predicting gender development in people with DSD.     

Defective,deleted or converted CYP21B gene and negative association with a rare restriction fragment length polymorphism allele of the factor B gene in congenital adrenal hyperplasia

Summary Defects in the enzyme, steroid 21-hydroxylase, result in congenital adrenal hyperplasia (CAH), a common autosomal recessive disorder of cortisol biosynthesis. The gene encoding this protein (CYP21B) and a closely linked pseudogene (CYP21A) have been mapped in the HLA complex on chromosome 6p, adjacent to the complement genes C4B and C4A, about 80 kb from the factor B gene. Molecular analyses of patients with CAH have shown that the cause of the defect may be either a deletion, a point mutation or a conversion of the active gene. Linkage of the disease to HLA has previously been studied by several groups. We have analyzed DNAs from patients with classical and non-classical CAH and from their family members, by probing with CYP21, C4 and BF cDNAs. In 70% of the CAH haplotypes studied, the defective CYP21B gene was indistinguishable from its structurally intact corresponding gene in Southern blot analysis, and presumably bore point mutations. In the remaining chromosomes, evidence for gene conversions, deletions and various deleterious mutations of the CYP21B gene is given. Moreover, our linkage studies show that a polymorphic TaqI cleavage site in the factor B gene, recently described by us, may be a new and useful genetic marker, because we found this TaqI restriction site only in unaffected haplotypes carrying functional CYP21B genes and, therefore, in negative association with the defective CYP21B gene.     

Females prefer the scent of outbred males: good-genes-as-heterozygosity?

Background  

There is increasing interest to determine the relative importance of non-additive genetic benefits as opposed to additive ones for the evolution of mating preferences and maintenance of genetic variation in sexual ornaments. The 'good-genes-as-heterozygosity' hypothesis predicts that females should prefer to mate with more heterozygous males to gain more heterozygous (and less inbred) offspring. Heterozygosity increases males' sexual ornamentation, mating success and reproduction success, yet few experiments have tested whether females are preferentially attracted to heterozygous males, and none have tested whether females' own heterozygosity influences their preferences. Outbred females might have the luxury of being more choosey, but on the other hand, inbred females might have more to gain by mating with heterozygous males. We manipulated heterozygosity in wild-derived house mice (Mus musculus musculus) through inbreeding and tested whether the females are more attracted to the scent of outbred versus inbred males, and whether females' own inbreeding status affects their preferences. We also tested whether infecting both inbred and outbred males with Salmonella would magnify females' preferences for outbred males.     

Yolk testosterone, postnatal growth and song in male canaries

Avian eggs contain substantial amounts of maternal yolk androgens, which have been shown to modulate offspring phenotype. The first studies on the functional consequences of maternal yolk androgens have focused on early life stages and their role in sibling competition. However, recent longitudinal studies reported long-lasting effects of maternal yolk androgens on offspring phenotype, mostly concerning traits that are sensitive to androgens. This suggests that maternal yolk androgens could play an important role in sexual selection, since the expression of many male sexual characters is testosterone-dependent. Using male canaries as a model, we examined the consequences of an experimental elevation of yolk testosterone concentrations on early development as well as long-lasting effects particularly on song, which is one of the most important sexual characters in male songbirds. Elevated yolk testosterone concentrations inhibited male growth, possibly in interaction with an existent ectoparasite exposure. Males hatched from testosterone-treated eggs (T-males) did not have enhanced competitive skills, in contrast to previous studies. The elevation of yolk testosterone concentrations delayed song development but did not affect adult song phenotype. This is intriguing, as yolk testosterone possibly induced developmental stress, which is known to reduce song quality. We hypothesize that yolk testosterone has either no direct effect on adult song phenotype, or that positive effects are merged by the negative effects of developmental stress. Finally, females mated with T-males invested more in their clutch indicating that females either assess T-males as more attractive (differential allocation hypothesis) or compensated for lower offspring viability (compensation hypothesis).     

Sex differences in children's free drawings: a study on girls with congenital adrenal hyperplasia

Sex differences are recognized in children's free drawings with respect to motifs, colors, figure compositions, and expression. Boys tend to draw mobile objects and mechanical objects with dark or cold colors and often use bird's-eye-view composition when they draw pictures, whereas girls like to draw human motifs (especially girls and women), flowers, and butterflies with light and warm colors and tend to arrange motifs in a row on the ground. Analyses were made on the drawings of girls with congenital adrenal hyperplasia (CAH) and unaffected boys and girls, using masculine and feminine indexes. Sex difference in masculine and feminine indexes was clear in the drawings by unaffected boys and girls. Their drawings do not or mostly do not contain characteristics typical of the opposite sex. Compared with those of unaffected girls, the pictures of CAH girls more strongly showed masculine characteristics. The feminine index for the pictures of CAH girls was significantly lower than that for unaffected girls, while the masculine index for CAH girls was significantly higher than that for unaffected girls. Furthermore, the masculine index for CAH girls was not significantly different from that of unaffected boys. These results suggest that androgen exposure during fetal life may contribute to shaping masculine characteristics in children's free drawings.     

A new DNA diagnostic system for the detection of human <Emphasis Type="Italic">CYP21</Emphasis> gene mutations associated with adrenal cortex hyperplasia

Congenital Adrenal Hyperplasia (CAH) is one of the most widespread severe autosomal recessive hereditary diseases. CAH is caused by the impaired biosynthesis of the key human hormones cortisol and aldosterone and is accompanied by the excess synthesis of androgens. Over 90% of CAH cases are caused by a deficiency of the steroid 21-hydrohylase (P450c21). The degree of damage in this enzyme is responsible for the severity of the clinical manifestation of CAH from potentially lethal to mild symptoms. Various mutations of the gene encoding this enzyme are the main source of the reduced activity of the steroid-21-hydrolase. The location of the highly homological pseudogene CYP21P in close proximity to the functional gene impedes the DNA diagnostics of CAH. To detect the eight most frequent CYP21 gene mutations associated with CAH, we developed a new real-time PCR-based system of DNA diagnostics using new allele-specific primers and TaqMan probes for the analyzed mutations. The method was primarily tested on artificial DNA templates, where the analyzed mutations were introduced by site-directed mutagenesis. Then, it was tested on DNA samples from 43 patients with clinical and biochemical manifestations of CAH; seven patients were used as a control. Two mutant alleles were detected in two different individuals: the nonsense Q318X and the missense V281L mutations.     

Responses to animal stimulus photographs in stumptailed macaques (Macaca arctoides)

Interest in their animate environment was studied in a captive group of 11 stumptailed macaques (Macaca arctoides). Subjects were shown projected photographic slides, most of which showed a single individual primate or non-primate. The measure of interest was the duration of viewing. Results showed that adult females exhibited more interest towards stumptailed macaques versus other macaques species, and towards adult females carrying infants versus adult females alone. Data concerning non-primates showed that subjects were especially interested by photographs of felids; this effect was partly due to the presence of two frontal and conspicuous eyes in felids.     

Predation–Reproduction Conflict Resolution in the Hermit Crab, Clibanarius vittatus

Activities associated with courtship are often in conflict with avoiding elevated predation risk. In polygamous species with temporally restricted mating seasons, males should be less responsive to interruption of courtship by detection of elevated predation risk compared to females. We tested this prediction with the hermit crab Clibanarius vittatus. Courting males continued to execute pre‐copulatory behavior patterns when exposed to predator odors. However, in the presence of predator odors, fewer pairs were established. Exposing previously paired males and females to predator cues showed that males were unaffected in their motivation to form pairs, whereas females were no longer attractive to males following exposure to predator cues.     

Different female mating rates in different populations do not reflect the benefits the females gain from polyandry in the adzuki bean beetle

The question why females in many species mate with several males (polyandry) has engaged the interest of evolutionary biologists for many years, and many studies have been conducted on the nature of the benefits that the females gain from polyandry. To understand the variation of female mating rates among species and populations it is indispensable to test the prediction that females of more polyandrous populations experience larger fitness benefit than those of less polyandrous populations. We compared the fitness components of two strains of the adzuki bean beetle Callosobruchus chinensis that have genetically different female mating rates. We measured the number of hatched eggs of once-copulated females and twice-copulated females in each strain. The statistical interaction for the number of hatched eggs between the number of matings and strains was determined. The increase in the number of hatched eggs is larger for the lower mating-rate strain than for the higher mating rate strain. This means that females of the lower mating-rate strain would have larger fitness gain from polyandry than those of the higher mating-rate strain. The actual mating rates of females did not reflect female interests in adzuki bean beetles, suggesting they are affected by sexual conflict.     

Effect of differential host exposure on reproduction in the solitary ectoparasitoid Eupelmus vuilleti

We examined self-superparasitism in Eupelmus vuilleti (CRW.), a solitary ectoparasitoid of larvae of Callosobruchus maculatus (F.) which develop in cowpea seeds. The reproduction of isolated females was analysed in the presence of seeds containing 10 or 30 hosts for 24, 48, and 72 h. At the two host densities, female reproductive activity increased with host exposure time, but variations in offspring number per female were limited. The propensity of the females to self-superparasitise their hosts after long exposure times could explain these results. The offspring sex ratio was female biased but tended to 0.5 for longer exposure times. The absence of host renewal for a 3-day period was followed by an increase in self-superparasitism which reduced the parasitoid survival rate and by emergence of a lower number of females in the offspring. The offspring production was then analysed when females were provided with ten hosts a day or with 30 hosts every three days throughout their life span. The reduction of host renewal frequency did not affect male production but caused a reduction in the number of females emerging from the seeds. The importance of a high rate of self-superparasitism on the population biology of this parasitoid is discussed.     

Egg‐yolk androgen and carotenoid deposition as a function of maternal social environment in barn swallows Hirundo rustica

Evidence is mounting that female animals use egg‐yolk compounds (e.g. steroids, antioxidants) to adaptively engineer the quality of their offspring as a function of several maternal and environmental factors. Though adjustments to yolk allocation have been well‐characterized as a function of parental phenotypes, we know very little about how an individual's social environment influences yolk composition. Here, we consider how two types of yolk compounds, androgens and carotenoids, relate to the maternal social environment during the egg‐laying period, controlling statistically for known correlations between various aspects of parental quality and egg yolk compounds. Barn swallows Hirundo rustica erythrogaster breed in groups of highly variable size and spacing, allowing us to test whether or not the social environment is correlated with these maternal effects. We found no relationship between carotenoid levels in eggs as a function of colony size, colony density, or nearest‐neighbor distance. However, eggs from females in larger groups had lower concentrations and total amounts of yolk androgens than those from females in smaller, less dense social settings. Our results counter previous predictions and literature, showing that females breeding in large groups deposit more androgen in eggs, mechanistically, because they compete more with conspecifics and have higher circulating androgen levels themselves and, functionally, because it could be advantageous for their offspring to show high androgen‐mediated competitive abilities early in life. Instead, because group size in this species is governed largely by site fidelity and the availability of old nests for re‐use, and because reproductive output does not differ as a function of group size, it may be that competition is greater for limited nests in small groups, thus elevating androgen levels. Further, yolk androgens were previously shown to be affected by male quality, and the greater concentrations and amounts of yolk androgens in smaller sites may reflect differential allocation to darker males found at these sites.