Origins Of Sex Differences Research Articles

Independent effects of testosterone, estradiol, and sex chromosomes on gene expression in immune cells of trans- and cisgender individuals.

The origins of sex differences in human disease are elusive, in part because of difficulties in separating the effects of sex hormones and sex chromosomes. To separate these variables, we examined gene expression in four groups of trans- or cisgender individuals: XX individuals treated with exogenous testosterone (n=21), XY treated with exogenous estradiol (n=13), untreated XX (n=20), and untreated XY (n=15). We performed single-cell RNA-sequencing of 358,426 peripheral blood mononuclear cells. Across the autosomes, 8 genes responded with a significant change in expression to testosterone, 34 to estradiol, and 32 to sex chromosome complement with no overlap between the groups. No sex-chromosomal genes responded significantly to testosterone or estradiol, but X-linked genes responded to sex chromosome complement in a remarkably stable manner across cell types. Through leveraging a four-state study design, we successfully separated the independent actions of testosterone, estradiol, and sex chromosome complement on genome-wide gene expression in humans.

The influence of sex on the relations among spatial ability, math anxiety and math performance

BackgroundA large body of research has found stronger math anxiety in females and suggests that inferior spatial abilities (or attributes towards spatial abilities) in females compared to males are the origin of sex differences in math anxiety. PurposeTo fully explore the complex relationship among math anxiety, spatial abilities, math performance and sex differences, the current study examined spatial skills, working memory skills, math anxiety, and self-efficacy as predictors of math performance. Basic proceduresParticipating in the study were 89 undergraduate Israeli students (44 males and 45 females). Main findingsThe result showed sex differences in a few domains: math anxiety was higher in females compared to males, males outperformed females in number line performance and spatial skills. The relationships among spatial abilities, math performance, and math anxiety were stronger in males than in females. By contrast, the relationship between math self-efficacy and performance was stronger in females compared to males. ConclusionsThis finding demonstrated fundamental differences between the sexes, even with similar performances in curriculum-based assessments.

Abstract P183: Contribution Of Childhood Risk Factors To Sex Differences In Adult Carotid Imt And Plaques: The Childhood Determinants Of Adult Health Study

Background: Understanding the origins of sex differences in cardiovascular diseases (CVD) may help with prevention. We examined sex differences in carotid artery IMT and plaques in adulthood including the contribution of childhood risk factors. Methods: Boys and girls aged 7-15 years old from the Australian Schools Health and Fitness Survey in 1985 were followed up in the Childhood Determinants of Adult Health study at ages 36-49 years between 2014-19. Sex differences in adult carotid IMT and plaques, identified with 2D ultrasound of left and right carotid arteries, were examined with linear and log binomial regression, respectively. Childhood sociodemographic, psychosocial, health-related behavioural and biomedical risk factors that might contribute to sex differences in carotid IMT/plaques were identified with purposeful model building. Results: Among 1,286 men and women with vascular measurements of carotid IMT (53% women, mean carotid IMT 0.63 mm ± 0.09 standard deviation) women had thinner carotid IMT measurements than men (β coefficients -0.053 95% CI -0.063, -0.043). Adjusting for age standardised waist circumference (WC), waist/hip ratio (WHR), waist/height ratio (WHtR) and systolic blood pressure (SBP) in childhood reduced the sex difference of carotid IMT in adulthood (see Figure), but a significant sex-difference in carotid IMT remained. Women had a 42% lower risk of plaques than men (Relative Risk 0.58 95% CI 0.42, 0.79). School achievement levels, endurance/power fitness and SBP in childhood partially explained the sex difference in the prevalence of plaques at adulthood (see Figure) as the sex difference decreased and became statistically insignificant. Conclusion: Various factors in childhood had contributed to thicker carotid IMT and higher prevalence of carotid plaques in men compared to women. These findings suggest that the origins of adult sex differences in CVD may begin in childhood. There may be benefits of sex-specific primary prevention programs starting in childhood.

Sex differences in moral judgements across 67 countries.

Most of the empirical research on sex differences and cultural variations in morality has relied on within-culture analyses or small-scale cross-cultural data. To further broaden the scientific understanding of sex differences in morality, the current research relies on two international samples to provide the first large-scale examination of sex differences in moral judgements nested within cultures. Using a sample from 67 countries (Study 1; n = 336 691), we found culturally variable sex differences in moral judgements, as conceptualized by Moral Foundations Theory. Women consistently scored higher than men on Care, Fairness, and Purity. By contrast, sex differences in Loyalty and Authority were negligible and highly variable across cultures. Country-level sex differences in moral judgements were also examined in relation to cultural, socioeconomic, and gender-equality indicators revealing that sex differences in moral judgements are larger in individualist, Western, and gender-equal societies. In Study 2 (19 countries; n = 11 969), these results were largely replicated using Bayesian multi-level modelling in a distinct sample. The findings were robust when incorporating cultural non-independence of countries into the models. Specifically, women consistently showed higher concerns for Care, Fairness, and Purity in their moral judgements than did men. Sex differences in moral judgements were larger in individualist and gender-equal societies with more flexible social norms. We discuss the implications of these findings for the ongoing debate about the origin of sex differences and cultural variations in moral judgements as well as theoretical and pragmatic implications for moral and evolutionary psychology.

An evaluation of visuospatial skills using hands-on tasks.

Several tests of mental rotation ability have been used to investigate its development and the origins of sex differences. One of the most used tests is the mental rotation test (MRT) by Vandenberg and Kuse. A limitation of the MRT is that it is a pen-and-paper test with 2D images of 3D objects. This is a challenge to the ecological validity of the MRT because mental rotation typically involves physical 3D objects that are also physically manipulated. The purpose of the present study was to compare mental rotation ability as evaluated by the MRT to three new tasks with physical objects (toy bricks) that were physically manipulated. The different tasks allowed us to vary the processing demands on mental rotation while standardizing other aspects of the tasks. Fifty-nine females and twenty-eight males completed the LMR and HMR conditions (low- and high-mental rotation demands, respectively) of the brick building task (BBT), a visual search task, and the MRT. As demands on mental rotation for the BBT increased, performance decreased and a sex difference, with males outperforming females, increased. There were correlations between all tasks, but they were larger between the versions of the BBT with the MRT. The results suggest that spatial skill is an assembly of interrelated subskills and that the sex difference is sensitive to the demands on mental rotation and dimensionality crossing. The benefits of the BBT are that it is ecologically valid, avoids dimensionality crossing, and the demands on mental rotation can be manipulated.

Sexual dimorphism in the physiological response of the Apoe −/− atherosclerosis model to sleep fragmentation

Abstract Sleep fragmentation (SF) is tightly correlated with the development of chronic low grade inflammatory diseases such as, type 2 diabetes and atherosclerosis; however, the exact relationship between SF and atherogenesis is unknown. Little evidence exists regarding the origin of sex differences in sleep behavior. While the role of gender has been studied in atherosclerosis, the impact of gender in SF-associated atherogenesis is not known. Recently, we have shown that high fat diet (HFD) fed male Apolipoprotein E-deficient (Apoe−/−)mice on SF unexpectedly experienced premature death, with 80% of males not surviving past week 2 of SF, while 80% of females survived past week 8 under the same conditions. To investigate the gender effects, male and female Apoe−/− mice were fed a HFD and SF for 10 days. Following HFD and SF, male mice, but not female Apoe−/− mice had enlarged hearts and lymph nodes, as well as peritoneal bleeding. Further, SF resulted in a significantly higher amount of circulating LPS and alterations in the immune composition of bone marrow (BM), blood, and lymph nodes (LN) in male HFD fed Apoe−/− mice vs SF female Apoe−/− mice. We detected a significant decrease in myeloid cells in the BM and blood, as well as a decrease in the percentage of T and B cells in the LN of HFD fed-SF males’ vs diet matched SF females. Interestingly, when male Apoe−/− mice were administered 17b-estradiol orally, in supplement with HFD feeding and SF, they survived past the 14 day death window. Altogether, SF alters the immune response in male atherosclerotic Apoe−/− mice resulting in early death. Our data suggests that the hormonal landscape in female Apoe−/− mice protects against SF-induced premature death via estrogen-dependent mechanisms.

Sex differences in exploratory behaviour of the common toad, Bufo bufo

The origin of sex differences in spatial behaviour is widely discussed in the laboratory studies in higher vertebrates, but almost nobody has investigated the problem in the first tetrapods, in amphibians. We tested exploratory behaviour, the crucial element of spatial behaviour, in 12 males and 7 females of the common toad, Bufo bufo, in a rectangular maze with four rooms and visual objects inside. One of the four rooms contained the useful resources (water, food, shelter). In the first 4 hr-trial toads explored the maze with the resources. In the second 4 hr-trial, 15 min later, the same environment contained no resources, and we evaluated the changes in the extent of movements and spatial preferences as the result of exploratory learning. In the first trial females moved widely among the rooms, while males more often visited the room with the resources. However, both sexes spent most of the time in the room with the resources. When the resources disappeared, males increased locomotory activity and the frequency of visits to the rooms. The activity of females remained almost unchanged. Toads were not motivated to search resources directly, as the latency to enter the resource room remained the same in both trials. Instead of this, toads monitored the potential location of the useful resources during the test, but the exploratory strategies of sexes were different. Males travelled mainly in the resource room. Females spent more time and more often visited two rooms: the resource and the opposite one. Thus, males demonstrated more intensive and more goal-oriented exploratory behaviour than females. It is the first evidence of sex differences in exploratory behaviour of amphibians obtained under controlled laboratory conditions.

Prenatal exposure to dexamethasone in the mouse induces sex-specific differences in placental gene expression.

Prenatal stress during pregnancy leads to sex-specific effects on fetal development and disease susceptibility over the life span; however, the origin of sex differences has not been identified. The placenta not only plays a key role in fetal growth and development throughout pregnancy, but also affects the fetal programming underlying subsequent adult health and accounts. Therefore, sex-specific adaptation of the placenta may be central to the sex differences in fetal growth and survival. Here, we analyzed the effects of prenatal dexamethasone (Dex) on sex-specific changes in placental gene expression using RNA-Seq. Placental tissues from males and females were separated into two developmentally distinct fetal and maternal parts at E11.5 stage. The majority of genes in female placentas were downregulated by prenatal Dex, whereas those were mostly maintained or rather upregulated in male placentas. RNA-Seq results were validated using independent biological replicates from the same stage and placental tissue samples from E18.5 by realtime PCR assays. Activation of various inflammatory response-related genes, chemokines and their receptors, particularly in male placentas, strongly implies that prenatal Dex exposure causes sex-specific physiological responses that can lead to inflammatorydiseases involving vascularpathology.

Attentional capture by social stimuli in young infants.

We investigated the possibility that a range of social stimuli capture the attention of 6-month-old infants when in competition with other non-face objects. Infants viewed a series of six-item arrays in which one target item was a face, body part, or animal as their eye movements were recorded. Stimulus arrays were also processed for relative salience of each item in terms of color, luminance, and amount of contour. Targets were rarely the most visually salient items in the arrays, yet infants' first looks toward all three target types were above chance, and dwell times for targets exceeded other stimulus types. Girls looked longer at faces than did boys, but there were no sex differences for other stimuli. These results are interpreted in a context of learning to discriminate between different classes of animate stimuli, perhaps in line with affordances for social interaction, and origins of sex differences in social attention.

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.

Knowing Your Own Mate Value

Knowing one’s mate value (mate-value accuracy) is an important element in reproductive success. We investigated within- and between-sex differences in this ability in a real-life speed-dating event. A total of 190 men and 192 women filled out a personality questionnaire and participated in speed-dating sessions. Immediately after each date, participants recorded who they would choose as mates and who they expected would choose them. In line with evolutionarily informed hypotheses, results indicated that sociosexually unrestricted men and more agreeable women showed greater mate-value accuracy than sociosexually restricted men and less agreeable women, respectively. These results have important implications for understanding mating behavior and perhaps the origin of sex differences in personality.

The nature and nurture of intelligence and motivation in the origins of sex differences in elementary school achievement

This study investigates the roles of intelligence and school‐related motivation in sex differences in school achievement and whether there are sex differences in the genetic and environmental influences on these variables. In a sample of 4464 9‐year‐old twins, intelligence, ablility self‐perceptions, intrinsic values and achievement scores were assessed. Girls outperformed boys in English and had better corresponding ability self‐perceptions, whereas in Math boys showed better attainment and ability self‐perceptions. For both sexes and all three domains, intelligence was the strongest predictor of achievement and ability self‐perceptions added incrementally to the prediction. Evidence of genetic influences was found for all measures but shared environmental influences were not important. These findings challenge some widely held assumptions about the development of children's motivation. Copyright © 2008 John Wiley & Sons, Ltd.

Estrogen receptor 1 polymorphisms are associated with airway hyperresponsiveness and lung function decline, particularly in female subjects with asthma

Sex hormones may contribute to the higher prevalence and severity of adult asthma in women compared with men. Sequence variants in the estrogen receptor alpha gene (ESR1) may alter estrogen action in asthma. Two hundred asthma probands and their families (n=1249) were genotyped for 5 single nucleotide polymorphisms (SNPs) in the ESR1 gene (intervening sequence 1 [IVS1]-1505A/G, IVS1-1415T/C, IVS1-397C/T, IVS1-351G/A and exon1+30T/C). Association with asthma and bronchial hyperresponsiveness (BHR) were tested. In the asthma probands, association of SNPs with BHR severity and annual FEV1 decline were determined. No SNP was associated with asthma. IVS1-397 was significantly associated with the presence of BHR (P=.02) and interacted with sex; female subjects with the CT or TT genotype were at risk (P=.01). In asthma probands, all SNPs were associated with FEV1 decline. Exon1+30 CT and TT group had an excess decline of 11.6 mL/y (P=.03) and 15.7 mL/y (P=.01), respectively, compared with the CC group. Of the IVS1 polymorphisms, IVS1-351G/A showed the strongest association, with the AA group having excess decline of 16.1 mL/y (P=.01) compared with the GG group. In subanalyses by sex, these associations were significant only in female subjects. ESR1 gene variants may affect development of BHR, particularly in female subjects. They may also lead to a more rapid lung function loss in patients with asthma, and in female subjects specifically. This may result from altered estrogen action, which affects lung development and/or airway remodeling. Further studies on ESR1 gene variations are important to understand better the origin of sex differences in asthma. Variations in the gene encoding estrogen receptor alpha are associated with BHR and a more rapid annual lung function decline, especially in female subjects. Even though this has no diagnostic or clinical implication, it may open avenues for future sex-specific treatment in asthma.

Prospecting in the collared flycatcher: gathering public information for future breeding habitat selection?

Visiting breeding patches can allow prospecting individuals to gather information on local patch quality to make optimal decisions about selecting a breeding habitat in the following year. This prospecting behaviour has been described in many bird species. However, the nature of the information gathered by prospectors often remains unknown. We collected data on prospecting behaviour in the collared flycatcher, Ficedula albicollis, a small hole-nesting passerine bird, to investigate whether prospectors could gather information on their conspecifics' reproductive success, that is, ‘public information’. If they could, they would be expected to inspect conspecific nests, prospect at the time when public information is reliable, and be attracted to, and spend time at, successful sites. Prospecting at conspecific nests was frequent. Prospectors were mainly males, and prospecting activity closely matched the peak of nesting activity. The probability of observing a prospector at a nest increased with parental activity, measured by feeding rate and vigilance behaviour, but did not depend on direct measures of success of the inspected nest (nestling number and condition), or on female characteristics. Because feeding rate and vigilance behaviour were predictors of breeding success at fledging, prospectors were attracted to the most successful nests when cueing on conspicuous parental activity. Therefore, prospectors could gather accurate information on local conspecific reproductive success that may be used for breeding patch choice in the following year. We discuss alternative explanations for our results, and the need to test experimentally whether prospectors gather public information. We also discuss the role of breeding constraints on, and the origin of sex differences in, prospecting.

A cross-cultural analysis of the behavior of women and men: Implications for the origins of sex differences.

A cross-cultural analysis of the behavior of women and men: Implications for the origins of sex differences.

Once again, the origins of sex differences.

Once again, the origins of sex differences.

Once again, the origins of sex differences.

Once again, the origins of sex differences.

The origins of sex differences in human behavior: Evolved dispositions versus social roles.

The origins of sex differences in human behavior: Evolved dispositions versus social roles.

The origins of sex differences in human behavior: Evolved dispositions versus social roles.

The origins of sex differences in human behavior: Evolved dispositions versus social roles.

On the origins of sex differences in social behavior: Darwinian and non-Darwinian accounts.

On the origins of sex differences in social behavior: Darwinian and non-Darwinian accounts.