Beyond masculinity: testosterone, gender/sex, and human social behavior in a comparative context

Adverse childhood experiences and intimate partner violence in adulthood among transgender women: exploring the chain mediating role of self-esteem and LGBT minority stress

BACKGROUND

Transgender women experience a high incidence of intimate partner violence (IPV) in adulthood. The well-documented risk factors contributing to IPV include adverse childhood experiences (ACEs), low self-esteem, and the minority stress experienced by LGBT individuals. The object of the present study was to examine how ACEs influence IPV in adulthood, and to explore the chain mediating function of self-esteem and LGBT minority stress.

METHODS

In February 2022, we recruited 264 transgender women through snowball sampling in Shenyang, China. Participants completed a questionnaire assessing background characteristics, ACEs, IPV in adulthood, self-esteem and LGBT minority stress. Relationships among study variables were examined through variance and correlation analyses. A chain mediation model was tested using PROCESS.

RESULTS

There was a significant correlation among the four variables. ACEs positively predicted IPV in adulthood (r = 0.449, p < 0.001). The sequential mediation model demonstrated that self-esteem (the estimated effect = 0.0708, 95%CI: 0.0152-0.1327) and minority stress (the estimated effect = 0.0404, 95%CI: 0016-0.0847) had the potential to mediate the connection between ACEs and IPV respectively. Additionally, the combined mediating influence of self-esteem and minority stress (the estimated effect = 0.0298, 95%CI: 0.0105-0.0591) similarly exerted such an effect. In summary, the mediating effect accounts for 34.59% of the overall effect size.

CONCLUSION

Taken together, the findings underscore the high prevalence of IPV among Chinese transgender women, highlighting the need for additional attention from violence service providers and other healthcare professionals on ACEs, low self-esteem, and minority stress, as these factors may place this population at risk for IPV.

Causal Attributions of Low Sexual Desire in Women Partnered with Men

Low sexual desire in women partnered with men has been the subject of controversy and research over the past decades, including both as construct and diagnosis. Despite discussion surrounding the causes of low desire, there is a gap in research about how women themselves understand the causes of their low desire and the potential consequences of these causal attributions. In the current study, we investigated this by asking 130 women who had low desire and were partnered with men about their attributions for low desire. Through content analysis, we identified five attribution categories: psychological/individual, relational, biological, sociocultural, and/or sexual orientation/identity/status. Many participants chose more than one category, indicating a multifaceted nature of women's causes of low desire. We then quantitatively assessed women's feelings of responsibility for, and emotions surrounding, their low desire. Our findings indicate that the majority-but not all-of women have negative feelings about their low desire. However, the specific emotions they experience are related to their attribution patterns. This underscores the significance of investigating various facets of women's attributions regarding low desire in order to gain a more comprehensive understanding of their emotional experiences and desire overall.

The Influence of Sex and Gender on the Level and Course of Subjective Cognitive Complaints After Percutaneous Coronary Intervention

BACKGROUND

Cognitive complaints (e.g., health anxiety and illness disruption) are commonly experienced by patients with coronary heart disease (CHD). While it is known that sex and gender affect health, their influence on cognitive complaints remains unknown. The current study explored sex and gender differences in cognitive complaints during the first month (acute phase) and beyond, up to 2 years (recovery phase) after percutaneous coronary intervention (PCI).

METHOD

A total of 514 (Mage = 64.2 ± 8.9, 84.2% male) completed the cognitive scale of the Health Complaints Scale (i.e., overall cognitive complaints, health worry, illness disruption) at baseline, 1, 12, and 24 months post-PCI. Additional questionnaires to gauge gender identity, traits, and norms were administered in a follow-up study. General linear mixed model analyses were conducted to examine the influence of sex, gender, sex × gender, and covariates on cognitive complaints.

RESULTS

Cognitive complaints only decreased in the first month post-PCI (all p < .01). There were no clear sex differences. However, gender generally predicted cognitive complaints in the first 2 years post-PCI: masculinity was related to less complaints, whereas feminine individuals reported higher absolute levels of complaints.

CONCLUSION

The current findings reveal that gender is a valuable factor concerning health complaints and indicate the need to further elaborate on the discrepancies between sex and gender in health research.

Day-to-day associations between testosterone, sexual desire and courtship efforts in young men

Testosterone plays important roles in reproductive behaviour in many species. Despite a common belief that testosterone regulates fluctuations in human sexual desire, there is little direct evidence that relates within-person changes in natural testosterone production to within-person changes in sexual desire. Here, we measured daily salivary testosterone concentrations from 41 adult men for one month, along with daily self-reports of sexual desire (n = 759 observations for the main analyses). We analysed concurrent relationships between within-person changes in testosterone and desire, and also lagged relationships that were analysed using a continuous-time modelling framework. We found no evidence for significant, positive relationships between testosterone and desire, which argues against the notion that day-to-day changes in eugonadal men's baseline testosterone regulates changes in their sexual desire. However, additional analyses provided preliminary evidence for a positive relationship between testosterone and self-reported courtship effort, particularly on days when single participants interacted with potential romantic partners. Our findings add original evidence regarding day-to-day associations between testosterone and desire, and suggest that testosterone above minimum threshold concentrations does not increase sexual desire. We propose that the evolved functions of testosterone in human males are more closely associated with courtship efforts than with sexual desire.

Modulation of the attentional response to baby schema by testosterone in pedohebephilic men and its relation to the nurturing system

Previous fMRI research found increased brain responses in men with pedophilic interest to non-sexual pictures of child and animal faces. This raised the question of whether an aberrant nurturing system could be linked to pedophilia. To further explore this hypothesis, 20 pedohebephilic and 23 teleiophilic men performed a target detection task with adult versus infant human and animal faces, which measured selective attention towards the baby schema by comparing reaction times to infant versus adult targets that were presented amongst distractors of the other category. Since the response to baby schema can be influenced by steroid hormones, saliva samples were additionally collected to determine endogenous testosterone, progesterone, estradiol and cortisol. Contrary to expectations, all men did not react faster to infant than adult faces. Yet, pedohebephilic men were more distracted by infant's faces than teleiophilic men. Pedohebephilic men with higher testosterone were faster in orienting attention to infant targets in the context of adult distractors. This association was not observed in teleiophilic men. Our results support the idea of an overactive nurturing system in pedophilia, which may be influenced by the endogenous testosterone level.

Testosterone, gender identity and gender-stereotyped personality attributes

Sex/gender differences in personality associated with gender stereotyped behavior are widely studied in psychology yet remain a subject of ongoing debate. Exposure to testosterone during developmental periods is considered to be a primary mediator of many sex/gender differences in behavior. Extensions of this research has led to both lay beliefs and initial research about individual differences in basal testosterone in adulthood relating to "masculine" personality. In this study, we explored the relationships between testosterone, gender identity, and gender stereotyped personality attributes in a sample of over 400 university students (65 % female assigned at birth). Participants provided ratings of their self-perceived masculinity and femininity, resulting in a continuous measure of gender identity, and a set of agentic and communal personality attributes. A saliva sample was also provided for assay of basal testosterone. Results showed no compelling evidence that basal testosterone correlates with gender-stereotyped personality attributes or explains the relationship between sex/gender identity and these attributes, across, within, or covarying out sex assigned at birth. Contributing to a more gender diverse approach to assessing sex/gender relationships with personality and testosterone, our continuous measure of self-perceived masculinity and femininity predicted additional variance in personality beyond binary sex and showed some preliminary but weak relationships with testosterone. Results from this study cast doubt on the activational testosterone-masculinity hypothesis for explaining sex differences in gender stereotyped traits and within-sex/gender variation in attributes associated with agency and communality.

The role of sex and gender in somatic complaints among patients with coronary heart disease: A longitudinal study on acute and long-term changes

BACKGROUND

Somatic complaints are persistently reported in patients with coronary heart disease (CHD). Sex and gender influence health and well-being in a variety of ways, but it is unknown how they affect somatic complaints over time after percutaneous coronary intervention (PCI). Therefore, we examined the association between sex and gender on somatic health complaints during the first month (acute) and the first two years (recovery) after PCI.

METHODS

514 patients (Mage = 64.2 ± 8.9, 84.2% male) completed the somatic scale of the Health Complaints Scale (including the subscales: cardiopulmonary complaints, fatigue, sleep problems) at baseline, one, 12-, and 24-months post-PCI. In a follow-up study, they filled in additional questionnaires to gauge gender norms, traits, and identity. Linear mixed modeling analyses were used to assess the influence of sex, gender, their interaction, and covariates on somatic complaints for the acute and recovery phases separately.

RESULTS

A general decline in somatic complaints over time was observed during the acute phase, followed by a stabilization in the recovery phase. Females and individuals with more feminine traits, norms, and identities reported increased somatic complaints. Males with more pronounced feminine norms and females with more masculine norms likewise reported more somatic, cardiopulmonary, and fatigue complaints. Furthermore, age, cardiac history, and comorbid diseases partly explained the associations with somatic complaints.

CONCLUSION

While somatic complaints improve post-PCI, there are still conspicuous sex and gender differences that need to be considered. Future research should further elaborate upon these discrepancies and incorporate sex and gender in prevention and develop tailored interventions to diminish somatic complaints.

Testosterone's role in modulating human behaviors relevant to mating and parenting

Testosterone (T) is linked to human mating and parenting. Here, we comprehensively reviewed evidence on whether, in men and women, (1) basal T levels are related to mating and parenting behaviors, (2) T responds to reproduction-relevant cues, (3) acute changes in T map onto subsequent mating and parenting behaviors, and (4) single-dose exogenous T administration causally affects mating and parenting behaviors. We examined whether the available evidence supports trade-off interpretations of T's adaptive function whereby high T levels correspond to greater mating/reproductive effort and competition and low T levels to greater parenting effort and nurturance. We found mixed support for trade-off hypotheses, suggesting that T's function in modulating human mating and parenting might be more nuanced and highly dependent on context and individual trait differences. Results were largely similar for men and women, although studies with women were scarcer than those with men for most behaviors we reviewed.

Testosterone facilitates nonreproductive, context-appropriate pro- and anti-social behavior in female and male Mongolian gerbils

A growing body of literature suggests that testosterone (T) rapidly modulates behavior in a context-specific manner. However, the timescales in which T can rapidly mediate distinct types of behavior, such as pro- vs. anti- social responses, has not been studied. Thus, here we examined acute T influences on social behavior in male and female Mongolian gerbils in nonreproductive contexts. Females and males received an injection of either saline or T and were first tested in a social interaction test with a same-sex, familiar peer. 5 min after the peer interaction, subjects then underwent a resident-intruder test with a novel, same-sex conspecific. After another 5 min, gerbils were tested in a novel object task to test context-specificity (i.e., social vs. nonsocial) of T effects on behavior. Within 1 h, males and females injected with T exhibited more huddling with a peer but more active avoidance of and less time spent in proximity of an intruder than did animals injected with saline. T effects on behavior were specific to social contexts, such that T did not influence investigation of the novel object. Together these findings show that T rapidly promotes pro-social responses to a familiar peer and anti-social responses to an intruder in the same individuals within 5 min of experiencing these disparate social contexts. This demonstrates that T rapidly facilitates behavior in a context-appropriate manner outside the context of reproduction and reveals that rapid effects of T on behavior are not restricted to males.

Prenatal testosterone synchrony in first-time parents predicts fathers' postpartum relationship quality

There is evidence that men's testosterone levels decline across the transition to fatherhood and that this decline may reflect fathers' investment in the new family. There is also emerging evidence that cohabiting couples show synchrony or within-couple associations in testosterone levels during the perinatal period. Hormonal synchrony may act as a mechanism that supports fathers' biological preparation for parenthood, perhaps by facilitating perinatal declines in paternal testosterone. However, few studies have examined testosterone synchrony and change within couples. A sample of 97 U.S. couples expecting their first child provided testosterone samples during pregnancy, and of those couples, 78 couples also provided testosterone at seven months postpartum. Couples reported on relationship satisfaction both at prenatal and postpartum visits. Bayesian multilevel modeling revealed within-couple testosterone synchrony both during pregnancy and postpartum. Testosterone synchrony during pregnancy predicted a greater drop in fathers' testosterone levels from prenatal to postpartum and higher paternal postpartum relationship quality. Fathers' lower prenatal testosterone levels also subsequently predicted higher self-reported postpartum relationship quality for both parents. In sum, this study finds that couples' testosterone levels show synchrony across the transition to parenthood in ways that are associated with couple relationship quality and men's neuroendocrine preparation for fatherhood.

Hormone physiology and sleep dynamics among BaYaka foragers of the Congo Basin: Gendered associations between nighttime activity, testosterone, and cortisol

Sleep quality is an important contributor to health disparities and affects the physiological function of the immune and endocrine systems, shaping how resources are allocated to life history demands. Past work in industrial and post-industrial societies has shown that lower total sleep time (TST) or more disrupted nighttime sleep are linked to flatter diurnal slopes for cortisol and lower testosterone production. There has been little focus on these physiological links in other socio-ecological settings where routine sleep conditions and nighttime activity demands differ. We collected salivary hormone (testosterone, cortisol) and actigraphy-based sleep data from Congolese BaYaka foragers (N = 39), who have relatively short and fragmented nighttime sleep, on average, in part due to their typical social sleep conditions and nighttime activity. The hormone and sleep data collections were separated by an average of 11.23 days (testosterone) and 2.84 days (cortisol). We found gendered links between nighttime activity and adults' hormone profiles. Contrary to past findings in Euro-American contexts, BaYaka men who were more active at night, on average, had higher evening testosterone than those with lower nighttime activity, with a relatively flat slope relating nighttime activity and evening testosterone in women. Women had steeper diurnal cortisol curves with less disrupted sleep. Men had steeper cortisol diurnal curves if they were more active at night. BaYaka men often hunt and socialize when active at night, which may help explain these patterns. Overall, our findings indicate that the nature of nighttime activities, including their possible social and subsistence contexts, are potentially important modifiers of sleep quality-physiology links, meriting further research across contexts.

The prognostic role of sex and hemoglobin levels in patients with oral tongue squamous cell carcinoma

Background

Women and men differ genetically, biologically (sex) and by social construct (gender), possibly impacting on prognostic factors in predicting cancer survival. Hemoglobin levels and immune system activation are players acting in this scenario which could play a role in partly determining prognosis between patients of different sex/gender (S/G). Here, we investigate these factors in patients affected by tongue squamous cell carcinoma.

Methods

This is an observational retrospective cohort study. We collected tongue cancer patients' clinical data, including hemoglobin levels and neutrophil lymphocyte ratio (NLR). Overall survival (OS) and disease-free survival (DFS) were compared between women and men considering confounding and prognostic factors in multivariate Cox proportional hazard models. Stratified analyses were also conducted by sex and tumor stage.

Result

576 patients, 39.9% women and 60.1% men, were found eligible for the analysis. Men were more often smokers (p<0.001), alcohol consumers (p<0.001), overweight or obese (p<0.001) and undergoing radiotherapy (p=0.002). In multivariate models for stage I-II, men showed half risk of death and relapse compared to women (HR=0.44; 95%CI 0.24-0.81, p=0.009; HR=0.55; 95%CI 0.34-0.87, p=0.01, for OS and DFS respectively). Moreover, low hemoglobin levels appeared to be an independent prognostic factor for women but not for men in terms of both OS and DFS. Specifically, women with low hemoglobin levels showed a worse tumor outcome (HR=2.66; 95%CI 1.50-4.70; HR=2.09; 95%CI 1.24-3.53, for OS and DFS respectively). Low hemoglobin levels appeared to be a poor OS prognostic factor for women at stage I-II (p<0.004) but not for men (p=0.10). Women with advanced stage tumors, NLR>2.37, who did not performed Radiotherapy and with depth of invasion (DOI)> 10 were associated with a significant increase in relapse and death (all p<0.05).

Conclusion

In our cohort of patients with oral tongue squamous cell carcinoma, men present better OS and DFS than women with early stages tumors. Low hemoglobin level was an independent prognostic factor for women, especially at early-stage tumors. For advanced stages (III-IV), sex is not a significant factor related to patients' prognosis.

Bride price, dowry, and young men with time to kill: A commentary on men's marriage postponement in India

Rising numbers of young unmarried men in India reflect a marriage squeeze that goes beyond the shortage of brides created by sex-selective abortion. We describe a decline in men's marriageability caused by their falling economic prospects at the same time as families of brides are increasingly seeking grooms with stable employment. We group young men into those without jobs or much education, those with education but no work, and the privileged few with education as well as employment. This classification resolves some of the seeming contradictions in the qualitative literature on marriage in India. Some of this literature talks about the rising prevalence of bride price and some about the persistence of dowry, while some papers reflect in general on the costs of being young, male, and aimless. Our commentary includes a review of the growing literature on the physiological and (perhaps) consequently behavioural and health outcomes of men's anomie.

An Empirical Investigation of the Roles of Biological, Relational, Cognitive, and Emotional Factors in Explaining Sex Differences in Dyadic Sexual Desire

One challenge many marital couples face is that they experience discrepant levels of sexual desire for one another. Such discrepancies are particularly likely to arise in mixed-sex relationships because, at least in long-term relationships, men tend to have higher levels of sexual desire for their partner than do women. But what underlies this sex difference? We used a dyadic study of 100 mixed-sex community-based newlywed spouses to investigate the role of biological, relational, cognitive, and emotional factors in explaining sex differences in dyadic sexual desire for a long-term partner. Consistent with predictions, wives on average reported lower daily sexual desire for their spouse than did husbands. Moreover, individual differences in men's and women's levels of circulating testosterone explained this sex difference whereas relational (marital satisfaction, commitment), cognitive (sex-role identification, stress, self-esteem), and emotional (mood, depressive symptoms) factors did not. These findings advance our knowledge of factors that influence dyadic sexual desire and may have practical implications for treating relationship distress in mixed-sex marriages.

Fairly Criticized, or Politicized? Conflicts in the Neuroscience of Sex Differences in the Human Brain

Investigations of sex differences in the human brain take place on politically sensitive terrain. While some scholars express concern that gendered biases and stereotypes remain embedded in scientific research, others are alarmed about the politicization of science. To help better understand these debates, this review sets out three kinds of conflicts that can arise in the neuroscience of sex differences: academic freedom versus gender equality; frameworks, background assumptions, and dominant methodologies; and inductive risk and social values. The boundaries between fair criticism and politicization are explored for each kind of conflict, pointing to ways in which the academic community can facilitate fair criticism while protecting against politicization.

Hormonal contraceptives as disruptors of competitive behavior: Theoretical framing and review

Emerging evidence suggests that hormonal contraceptives (HCs) impact psychological outcomes through alterations in neurophysiology. In this review, we first introduce a theoretical framework for HCs as disruptors of steroid hormone modulation of socially competitive attitudes and behaviors. Then, we comprehensively examine prior research comparing HC users and non-users in outcomes related to competition for reproductive, social, and financial resources. Synthesis of 46 studies (n = 16,290) led to several key conclusions: HC users do not show the same menstrual cycle-related fluctuations in self-perceived attractiveness and some intrasexual competition seen in naturally-cycling women and, further, may show relatively reduced status- or achievement-oriented competitive motivation. However, there a lack of consistent or compelling evidence that HC users and non-users differ in competitive behavior or attitudes for mates or financial resources. These conclusions are tentative given the notable methodological limitations of the studies reviewed. Implications and recommendations for future research are discussed.

Sex and gender terminology: a glossary for gender-inclusive epidemiology

There is increased interest in inclusion, diversity and representativeness in epidemiological and community health research. Despite this progress, misunderstanding and conflation of sex and gender have precluded both the accurate description of sex and gender as sample demographics and their inclusion in scientific enquiry aiming to distinguish health disparities due to biological systems, gendered experiences or their social and environmental interactions. The present glossary aims to define and improve understanding of current sex-related and gender-related terminology as an important step to gender-inclusive epidemiological research. Effectively, a proper understanding of sex, gender and their subtleties as well as acknowledgement and inclusion of diverse gender identities and modalities can make epidemiology not only more equitable, but also more scientifically accurate and representative. In turn, this can improve public health efforts aimed at promoting the well-being of all communities and reducing health inequities.

Evidence for an adolescent sensitive period to family experiences influencing adult male testosterone production

Across vertebrates, testosterone is an important mediator of reproductive trade-offs, shaping how energy and time are devoted to parenting versus mating/competition. Based on early environments, organisms often calibrate adult hormone production to adjust reproductive strategies. For example, favorable early nutrition predicts higher adult male testosterone in humans, and animal models show that developmental social environments can affect adult testosterone. In humans, fathers’ testosterone often declines with caregiving, yet these patterns vary within and across populations. This may partially trace to early social environments, including caregiving styles and family relationships, which could have formative effects on testosterone production and parenting behaviors. Using data from a multidecade study in the Philippines (n = 966), we tested whether sons’ developmental experiences with their fathers predicted their adult testosterone profiles, including after they became fathers themselves. Sons had lower testosterone as parents if their own fathers lived with them and were involved in childcare during adolescence. We also found a contributing role for adolescent father–son relationships: sons had lower waking testosterone, before and after becoming fathers, if they credited their own fathers with their upbringing and resided with them as adolescents. These findings were not accounted for by the sons’ own parenting and partnering behaviors, which could influence their testosterone. These effects were limited to adolescence: sons’ infancy or childhood experiences did not predict their testosterone as fathers. Our findings link adolescent family experiences to adult testosterone, pointing to a potential pathway related to the intergenerational transmission of biological and behavioral components of reproductive strategies.

Law, policy, biology, and sex: Critical issues for researchers

Researchers should be aware of how sex-difference science is (mis)applied in legal and policy contexts.

Number of sexual partners and serum testosterone levels in a population-based sample of unpartnered heterosexual men

BACKGROUND

The relationship between men's testosterone levels and their sexual behaviors is unclear as existing studies find mixed results.

OBJECTIVES

The key objective of this study is to assess whether men's testosterone levels are affected by sexual behaviors, and to explore whether this relationship varies by age. Specifically, this study addresses the question: Are men's testosterone levels affected by the number of sexual partners they accrue?

METHODS

This analysis was based on a nationally-representative sample of 977 unpartnered heterosexual men between the ages of 20 and 65 in the United States. Serum testosterone levels were measured from blood samples using isotope dilution liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) and the number of sexual partners in the past 12 months was ascertained from an Audio Computer-Assisted Personal Self-Interview (ACASI). Using ordinary least squares regression, serum testosterone levels were predicted as a function of the number of sexual partners that men reported, sociodemographic characteristics, and factors known to affect endocrine regulation. An interaction term between the number of sexual partners in the past 12 months and age was included.

RESULTS

The correlation between the number of sexual partners in the past 12 months and testosterone levels is contingent upon age: The relationship is positive for younger men but negative for older men. Among 20-year-old unpartnered heterosexual men, an additional sexual partner in the past 12 months is associated with an increase of 5.55 ng/dL of testosterone (95% CI: 2.92, 8.19). This initial positive effect at age 20 is reduced by 0.25 ng/dL of testosterone (95% CI: -0.44, -0.06) with each year that men age.

CONCLUSION

Testosterone levels in men are related to reproductive behaviors, but the direction of this relationship changes as men age. This article is protected by copyright. All rights reserved.

Endogenous oxytocin, cortisol, and testosterone in response to group singing

Humans have sung together for thousands of years. Today, regular participation in group singing is associated with benefits across psychological and biological dimensions of human health. Here we examine the hypothesis that a portion of these benefits stem from changes in endocrine activity associated with affiliation and social bonding. Working with a young adult choir (n = 71), we measured changes salivary concentrations of oxytocin, cortisol, and testosterone from before and after four experimental conditions crossing two factors: vocal production mode (singing vs. speaking) and social context (together vs. alone). Salivary oxytocin and cortisol decreased from before to after the experimental manipulations. For oxytocin the magnitude of this decrease was significantly smaller after singing compared to speaking, resulting in concentrations that were significantly elevated after singing together compared to speaking together, after controlling for baseline differences. In contrast, the magnitude of the salivary cortisol decreases was the same across experimental manipulations, and although large, could not be separated from diurnal cycling. No significant effects were found in a low-powered exploratory evaluation of testosterone (tested only in males). At a psychological level, we found that singing stimulates greater positive shifts in self-perceived affect compared to speaking-particularly when performed together-and that singing together enhances feelings of social connection more than speaking together. Finally, measurements of heart rate made for a subset of participants provide preliminary evidence regarding physical exertion levels across conditions. These results are discussed in the context of a growing multidisciplinary literature on the endocrinological correlates of musical behavior. We conclude that singing together can have biological and psychological effects associated with affiliation and social bonding, and that these effects extend beyond comparable but non-musical group activities. However, we also note that these effects appear heavily influenced by broader contextual factors that shape social dynamics, such as stress levels, the intimacy of interactions, and the status of existing relationships.

US fathers' reports of bonding, infant temperament and psychosocial stress based on family sleep arrangements

Background and objectives

Evolutionary-grounded sleep research has been critical to establishing the mutual dependence of breastfeeding and nighttime sleep proximity for mothers and infants. Evolutionary perspectives on cosleeping also often emphasize the emotional motivations for and potential benefits of sleep proximity, including for parent-infant bonding. However, this potential link between infant sleep location and bonding remains understudied for both mothers and fathers. Moreover, in Euro-American contexts bedsharing has been linked to family stress and difficult child temperament, primarily via maternal reports. We know relatively little about whether paternal psychosocial dynamics differ based on family sleep arrangements, despite fathers and other kin often being present in the cosleeping environment across cultures. Here, we aim to help address some of these gaps in knowledge pertaining to fathers and family sleep arrangements.

Methodology

Drawing on a sample of Midwestern U.S. fathers (N=195), we collected sociodemographic and survey data to analyze links between infant nighttime sleep location, paternal psychosocial well-being, father-infant bonding, and infant temperament. From fathers’ reports, families were characterized as routinely solitary sleeping, bedsharing, or roomsharing (without bedsharing).

Results

We found that routinely roomsharing or bedsharing fathers, respectively, reported stronger bonding than solitary sleepers. Bedsharing fathers also reported that their infants had more negative temperaments and also tended to report greater parenting-related stress due to difficulties with their children.

Conclusions

These cross-sectional results help to highlight how a practice with deep phylogenetic and evolutionary history, such as cosleeping, can be variably expressed within communities with the potential for family-dependent benefits or strains.

Evolutionary-grounded cosleeping research has elucidated the intimate connections between mother-infant sleep proximity and breastfeeding. However, some Euro-American research indicates that bedsharing can coincide with family strain and stress. Here, U.S. fathers who routinely roomshared or bedshared, respectively, reported stronger bonds to their babies than solitary sleeping fathers, but bedsharing fathers also reported more negative infant temperament.

Neurobiological Correlates of Fatherhood During the Postpartum Period: A Scoping Review

During the postpartum period, the paternal brain suffers extensive and complex neurobiological alterations, through the experience of father-infant interactions. Although the impact of such experience in the mother has been increasingly studied over the past years, less is known about the neurobiological correlates of fatherhood-that is, the alterations in the brain and other physiological systems associated with the experience of fatherhood. With the present study, we aimed to perform a scoping review of the available literature on the genetic, neuroendocrine, and brain correlates of fatherhood and identify the main gaps in the current knowledge. PubMed, Scopus, and Web of Science electronic databases were searched for eligible studies on paternal neuroplasticity during the postpartum period, over the past 15 years. Reference lists of relevant key studies and reviews were also hand-searched. The research team independently screened the identified studies based on the established inclusion criteria. Extracted data were analyzed using tables and descriptive synthesis. Among the 29 studies that met our inclusion criteria, the vast majority pertained to neuroendocrine correlates of fatherhood (n = 19), followed by brain activity or connectivity (n = 7), association studies of candidate genes (n = 2), and brain structure correlates (n = 1). Collectively, studies published during the past 15 years suggest the existence of significant endocrine (testosterone, oxytocin, prolactin, and cortisol levels) and neurofunctional alterations (changed activity in several brain networks related to empathy and approach motivation, emotional processing and mentalizing, emotion regulation, dorsal attention, and default mode networks) as a result of fatherhood, as well as preliminary evidence of genetic variability accounting for individual differences during the postpartum period in fathers. No studies were so far published evaluating epigenetic mechanisms associated with the paternal brain, something that was also the focus of the current review. We highlight the need for further research that examines neuroplasticity during the experience of fatherhood and that considers both the interplay between hormones and simultaneous assessment of the different biomarkers (e.g., associations between hormones and neural activity); data collection protocols and assessment times should also be refined.

Salivary Testosterone and Sexual Function and Behavior in Men and Women: Findings from the Third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3)

Using data from the third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3) we examined associations between salivary testosterone (Sal-T) and sexual function and behavior. Single morning saliva samples were self-collected from a subsample of participants aged 18-74 years and analyzed using mass spectrometry. 1,599 men and 2,123 women were included in the analysis (40.6% of those invited to provide a sample). We adjusted for confounders in a stepwise manner: in model 1 we adjusted for age only; model 2 for age, season and relationship status, and model 3 we added BMI and self-reported health. In the fully adjusted models, among men, Sal-T was positively associated with both partnered sex (vaginal sex and concurrent partners) and masturbation. Among women, Sal-T was positively associated with masturbation, the only association with partnered sex was with ever experience of same-sex sex. We found no clear association between Sal-T and sexual function. Our study contributes toward addressing the sparsity of data outside the laboratory on the differences between men and women in the relationship between T and sexual function and behavior. To our knowledge, this is the first population study, among men and women, using a mass spectrometry Sal-T assay to do so.

Applying an Evolutionary Approach of Risk-Taking Behaviors in Adolescents

Risk-taking behaviors in adolescents have traditionally been analyzed from a psychopathological approach, with an excessive emphasis on their potential costs. From evolutionary theory we propose that risk-taking behaviors can be means through which adolescents obtain potential benefits for survival and reproduction. The present study analyses sex differences in three contexts of risk (i.e., risk propensity, expected benefits and risk perception) in the evolutionary specific domains and the predictive value of these domains over risk-taking behaviors, separately in female and male adolescents. 749 adolescents (females = 370) valued their risk perception, expected benefits and risk propensity through the Evolutionary Domain-Specific Risk Scale, as well as their engagement in risk-taking behaviors through the Risky Behavior Questionnaire. Male adolescents showed lower risk perception in two evolutionary domains, expected higher benefits in two other domains and showed higher risk propensity in six domains. Female adolescents showed lower risk perception in two domains. Additionally, risk perception, expected benefits and risk propensity in the evolutionary domains predicted the engagement in risk-taking behaviors in male adolescents, whereas in female adolescents only expected benefits and risk propensity showed a predictive effect over risk-taking behaviors. These results suggest the potential role of evolutionary mechanisms on risk-taking behaviors in adolescents. Results have practical implications for interventions programs aimed at reducing risk-taking behaviors. In addition to considering sex differences, intervention programs should consider alternative behaviors through which adolescents can reach their evolutionary goals, and handle the risks related to those behaviors that cannot be replaced but have potential benefits for adolescents.

The Heteronormativity Theory of Low Sexual Desire in Women Partnered with Men

Low sexual desire in women partnered with men is typically presumed to be a problem-one that exists in women and encourages a research agenda on causation and treatment targeting women. In this paper, we present a distinct way forward for research on low sexual desire in women partnered with men that attends to a more structural explanation: heteronormativity. A heteronormative worldview assumes that relationships and structures are heterosexual, gender (usually conflated with sex) is binary and complementary, and gender roles fit within narrow bounds including nurturant labor for women. We propose the heteronormativity theory of low sexual desire in women partnered with men, arguing that heteronormative gender inequities are contributing factors. We outline four hypotheses and their predictions related to: inequitable divisions of household labor, blurring of partner and mother roles, objectification of women, and gender norms surrounding sexual initiation. We discuss some mechanisms-social, physiological, and otherwise-for the heteronormativity theory, especially related to stress, objectification, and nurturance. We close by noting some limitations of our paper and the ways that the heteronormativity theory of low sexual desire in women partnered with men provides a rigorous, generative, and empirical way forward.

Psychobiological risk factors for suicidal thoughts and behaviors in adolescence: a consideration of the role of puberty

Suicide is the second leading cause of death among adolescents. While clinicians and researchers have begun to recognize the importance of considering multidimensional factors in understanding risk for suicidal thoughts and behaviors (STBs) during this developmental period, the role of puberty has been largely ignored. In this review, we contend that the hormonal events that occur during puberty have significant effects on the organization and development of brain systems implicated in the regulation of social stressors, including amygdala, hippocampus, striatum, medial prefrontal cortex, orbitofrontal cortex, and anterior cingulate cortex. Guided by previous experimental work in adults, we also propose that the influence of pubertal hormones and social stressors on neural systems related to risk for STBs is especially critical to consider in adolescents with a neurobiological sensitivity to hormonal changes. Furthermore, facets of the pubertal transition, such as pubertal timing, warrant deeper investigation and may help us gain a more comprehensive understanding of sex differences in the neurobiological and psychosocial mechanisms underlying adolescent STBs. Ultimately, advancing our understanding of the pubertal processes that contribute to suicide risk will improve early detection and facilitate the development of more effective, sex-specific, psychiatric interventions for adolescents.

The Effects of Gender Trouble: An Integrative Theoretical Framework of the Perpetuation and Disruption of the Gender/Sex Binary

In the Western world, gender has traditionally been viewed as binary and as following directly from biological sex. This view is slowly changing among both experts and the general public, a change that has been met with strong opposition. In this article, we explore the psychological processes underlying these dynamics. Drawing on previous work on gender performativity as well as gender as a performance, we develop a psychological framework of the perpetuation and disruption of the gender/sex binary on a stage that facilitates and foregrounds binary gender/sex performance. Whenever character, costume, and script are not aligned the gender/sex binary is disrupted and gender trouble ensues. We integrate various strands of the psychological literature into this framework and explain the processes underlying these reactions. We propose that gender trouble can elicit threat-personal threat, group-based and identity threat, and system threat-which in turn leads to efforts to alleviate this threat through the reinforcement of the gender/sex binary. Our framework challenges the way psychologists have traditionally treated gender/sex in theory and empirical work and proposes new avenues and implications for future research.

Challenging the binary: Gender/sex and the bio-logics of normalcy

BACKGROUND

We are witnessing renewed debates regarding definitions and boundaries of human gender/sex, where lines of genetics, gonadal hormones, and secondary sex characteristics are drawn to defend strict binary categorizations, with attendant implications for the acceptability and limits of gender identity and diversity.

AIMS

Many argue for the need to recognize the entanglement of gender/sex in humans and the myriad ways that gender experience becomes biology; translating this theory into practice in human biology research is essential. Biological anthropology is well poised to contribute to these societal conversations and debates. To do this effectively, a reconsideration of our own conceptions of gender/sex, gender identity, and sexuality is necessary.

METHODS

In this article, we discuss biological variation associated with gender/sex and propose ways forward to ensure we are engaging with gender/sex diversity. We base our analysis in the concept of "biological normalcy," which allows consideration of the relationships between statistical distributions and normative views. We address the problematic reliance on binary categories, the utilization of group means to represent typical biologies, and document ways in which binary norms reinforce stigma and inequality regarding gender/sex, gender identity, and sexuality.

DISCUSSION AND CONCLUSIONS

We conclude with guidelines and methodological suggestions for how to engage gender/sex and gender identity in research. Our goal is to contribute a framework that all human biologists can use, not just those who work with gender or sexually diverse populations. We hope that in bringing this perspective to bear in human biology, that novel ideas and applications will emerge from within our own discipline.

Not all "caregivers" are created equal: Liking, caring and facial expression responses to the baby schema as a function of parenthood and testosterone

The baby schema elicits care from potential caregivers. However, much of the research on the baby schema is based on self-report only. To address this issue, we explored the effects of baby schema and child age on facial expressions (EMG) and eye-blink startle, in addition to self-reported liking and caring for 43 men and 48 women (39 parents). Further, basal testosterone was assessed. All groups responded with liking and caring to high baby schema, but only women also responded with more positive facial expressions. Caring and smiling towards infants compared to first graders depended on parenthood and testosterone levels. Basal testosterone levels were negatively associated with overall responsiveness to children in women and fathers, but positively in non-fathers. Whereas the baby schema overall lead to positive affect and caring, the scope of these responses and the processes underlying them depended on gender, parenthood and hormonal status.

Fathers' oxytocin responses to first holding their newborns: Interactions with testosterone reactivity to predict later parenting behavior and father-infant bonds

Little is known about human fathers' physiology near infants' births. This may represent a period during which paternal psychobiological axes are sensitive to fathers' new experiences of interacting with their newborns and that can provide insights on how individual differences in fathers' biology relate to post-partum parenting. Drawing on a sample of men in South Bend, IN (U.S.), we report results from a longitudinal study of fathers' oxytocin, cortisol, and testosterone (N = 211) responses to their first holding of their infants on the day of birth and men's reported caregiving and father-infant bonding at 2-4 months post-partum (N = 114). First-time fathers' oxytocin was higher following first holding of their newborns, compared to their pre-holding levels. Contrasting with prior results, fathers' percentage change in oxytocin did not differ based on skin-to-skin or standard holding. Drawing on psychobiological frameworks, we modeled the interactions for oxytocin reactivity with testosterone and cortisol reactivity, respectively, in predicting father-infant outcomes months later. We found significant cross-over interactions for (oxytocin × testosterone) in predicting fathers' later post-partum involvement and bonding. Specifically, we found that fathers whose testosterone declined during holding reported greater post-partum play if their oxytocin increased, compared to fathers who experienced increases in both hormones. We also observed a similar non-significant interaction for (oxytocin × cortisol) in predicting fathers' post-partum play. Fathers whose testosterone declined during holding also reported less involvement in direct caregiving and lower father-infant bonding if their oxytocin decreased but greater direct care and bonding if their testosterone increased and oxytocin decreased. The results inform our understanding of the developmental time course of men's physiological responsiveness to father-infant interaction and its relevance to later fathering behavior and family relationships.

The gender-binary cycle: the perpetual relations between a biological-essentialist view of gender, gender ideology, and gender-labelling and sorting

Gender inequality is one of the most pressing issues of our time. A core factor that feeds gender inequality is people's gender ideology-a set of beliefs about the proper order of society in terms of the roles women and men should fill. We argue that gender ideology is shaped, in large parts, by the way people make sense of gender differences. Specifically, people often think of gender differences as expressions of a predetermined biology, and of men and women as different 'kinds'. We describe work suggesting that thinking of gender differences in this biological-essentialist way perpetuates a non-egalitarian gender ideology. We then review research that refutes the hypothesis that men and women are different 'kinds' in terms of brain function, hormone levels and personality characteristics. Next, we describe how the organization of the environment in a gender-binary manner, together with cognitive processes of categorization drive a biological-essentialist view of gender differences. We then describe the self-perpetuating relations, which we term the gender-binary cycle, between a biological-essentialist view of gender differences, a non-egalitarian gender ideology and a binary organization of the environment along gender lines. Finally, we consider means of intervention at different points in this cycle. This article is part of the theme issue 'The political brain: neurocognitive and computational mechanisms'.

Biocultural approaches to transgender and gender diverse experience and health: Integrating biomarkers and advancing gender/sex research

Transgender and gender diverse (TGD) people are increasingly visible in U.S. communities and in national media. With this increased visibility, access to gender affirming healthcare is also on the rise, particularly for urban youth. Political backlash and entrenchment in a gender binary, however, continue to marginalize TGD people, increasing risk for health disparities. The 2016 National Institute of Health recognition of sexual and gender minority people as a health disparities population increases available funding for much-needed research. In this article, we speak to the need for a biocultural human biology of gender/sex diversity by delineating factors that influence physiological functioning, mental health, and physical health of TGD people. We propose that many of these factors can best be investigated with minimally invasively collected biomarker samples (MICBS) and discuss how to integrate MICBS into research inclusive of TGD people. Research use of MICBS among TGD people remains limited, and wider use could enable essential biological and health data to be collected from a population often excluded from research. We provide a broad overview of terminology and current literature, point to key research questions, and address potential challenges researchers might face when aiming to integrate MCIBS in research inclusive of transgender and gender diverse people. We argue that, when used effectively, MICBS can enhance human biologists' ability to empirically measure physiology and health-related outcomes and enable more accurate identification of pathways linking human experience, embodiment, and health.

Sharing and caring: Testosterone, fathering, and generosity among BaYaka foragers of the Congo Basin

Humans are rare among mammals in exhibiting paternal care and the capacity for broad hyper-cooperation, which were likely critical to the evolutionary emergence of human life history. In humans and other species, testosterone is often a mediator of life history trade-offs between mating/competition and parenting. There is also evidence that lower testosterone men may often engage in greater prosocial behavior compared to higher testosterone men. Given the evolutionary importance of paternal care and heightened cooperation to human life history, human fathers' testosterone may be linked to these two behavioral domains, but they have not been studied together. We conducted research among highly egalitarian Congolese BaYaka foragers and compared them with their more hierarchical Bondongo fisher-farmer neighbors. Testing whether BaYaka men's testosterone was linked to locally-valued fathering roles, we found that fathers who were seen as better community sharers had lower testosterone than less generous men. BaYaka fathers who were better providers also tended to have lower testosterone. In both BaYaka and Bondongo communities, men in marriages with greater conflict had higher testosterone. The current findings from BaYaka fathers point to testosterone as a psychobiological correlate of cooperative behavior under ecological conditions with evolutionarily-relevant features in which mutual aid and sharing of resources help ensure survival and community health.

Changes in prenatal testosterone and sexual desire in expectant couples

During the transition to parenthood (TTP), both women and men report declines in sexual desire, which are thought to reflect an evolutionarily adaptive focus on parenting over mating. New parents also show changes in testosterone, a steroid hormone implicated in both parenting and mating, suggesting that changes in sexual desire may be associated with changes in testosterone. To test these associations, we followed a sample of heterosexual couples expecting their first child across the prenatal period. We examined prenatal changes in testosterone and two forms of sexual desire (solitary, dyadic). Expectant mothers showed prenatal increases in testosterone, and women's higher testosterone was associated with lower dyadic desire. Expectant fathers showed prenatal decreases in testosterone, and declines in men's testosterone were associated with lower dyadic desire. Testosterone was unrelated to men's or women's solitary desire. Our findings provide support for the idea that prenatal changes in testosterone contribute to an evolutionarily adaptive focus on parenting over mating during the TTP.

Collective action reduces androgen responsiveness with implications for shoaling dynamics in stickleback fish

Androgens, traditionally viewed as hormones that regulate secondary sexual characteristics and reproduction in male vertebrates, are often modulated by social stimuli. High levels of the 'social hormone' testosterone (T) are linked to aggression, dominance, and competition. Low T levels, in contrast, promote sociopositive behaviours such as affiliation, social tolerance, and cooperation, which can be crucial for group-level, collective behaviours. Here, we test the hypothesis that - in a collective context - low T levels should be favourable, using non-reproductive male and female stickleback fish (Gasterosteus aculeatus) and non-invasive waterborne hormone analysis. In line with our predictions, we show that the fishes' T levels were significantly lower during shoaling compared to when alone, with high-T individuals showing the largest decrease. Ruling out stress-induced T suppression and increased T conversion into oestradiol, we find evidence that shoaling directly affects androgen responsiveness. We also show that groups characterized by lower mean T exhibit less hierarchical leader-follower dynamics, suggesting that low T promotes egalitarianism. Overall, we show that collective action results in lower T levels, which may serve to promote coordination and group performance. Our study, together with recent complementary findings in humans, emphasizes the importance of low T for the expression of sociopositive behaviour across vertebrates, suggesting similarities in endocrine mechanisms.

Sex-Differentiated Changes in Sexual Desire Predict Marital Dissatisfaction

Sex is critical to marriage. Yet, there are several reasons to expect spouses to experience declines in the desire for sex over time, and the rates of any declines in sexual desire may differ for men and women. We used two multi-wave, longitudinal studies to test whether male and female members of newlywed couples experienced different rates of change in sexual desire, whether any such changes were accentuated by childbirth, and whether any such changes had implications for marital satisfaction. In both studies, spouses provided multiple reports of sexual desire, marital satisfaction, and childbirth. Results demonstrated that women's sexual desire declined more steeply over time than did men's sexual desire, which did not decline on average. Further, childbirth accentuated this sex difference by partially, though not completely, accounting for declines in women's sexual desire but not men's. Finally, declines in women's but not men's sexual desire predicted declines in both partners' marital satisfaction. These effects held controlling depressive symptoms and stress, including stress from parenthood. The current findings offer novel longitudinal evidence for sex-differentiated changes in sexual desire and therefore suggest an important source of marital discord.

Hormones in speed-dating: The role of testosterone and cortisol in attraction

There is evidence that testosterone and cortisol levels are related to the attraction of a romantic partner; testosterone levels relate to a wide range of sexual behaviors and cortisol is a crucial component in the response to stress. To investigate this, we conducted a speed-dating study among heterosexual singles. We measured salivary testosterone and cortisol changes in men and women (n = 79) when they participated in a romantic condition (meeting opposite-sex others, i.e., potential romantic partners), as well as a control condition (meeting same-sex others, i.e., potential friends). Over the course of the romantic speed-dating event, results showed that women's but not men's testosterone levels increased and cortisol levels decreased for both men and women. These findings indicate that men's testosterone and cortisol levels were elevated in anticipation of the event, whereas for women, this appears to only be the case for cortisol. Concerning the relationship between attraction and hormonal change, four important findings can be distinguished. First, men were more popular when they arrived at the romantic speed-dating event with elevated cortisol levels. Second, in both men and women, a larger change in cortisol levels during romantic speed-dating was related to more selectivity. Third, testosterone alone was unrelated to any romantic speed-dating outcome (selectivity or popularity). However, fourth, women who arrived at the romantic speed-dating event with higher testosterone levels were more selective when their anticipatory cortisol response was low. Overall, our findings suggest that changes in the hormone cortisol may be stronger associated with the attraction of a romantic partner than testosterone.

Chronotype, social jetlag and sleep loss in relation to sex steroids

Chronotype describes preferences for functioning at different times of the day. At the onset of puberty, a sharp shift towards eveningness starts, reaching its peak at the end of adolescence, followed by a steady shift towards morningness as the ageing process occurs. Puberty is also the time when sex differences appear, with men being more inclined to eveningness than women, which diminishes around menopause; the described pattern of changes in chronotype leads to the hypothesis that reproductive hormones may be the driving factor behind this conversion. In the present study, we aimed to verify this hypothesis by analysing participants' testosterone, progesterone and dehydroepiandrosterone (DHEA) levels in the three months, as indicated by assays in 3-cm hair strands from the scalp. Participants (n = 239) of both sexes also completed the Munich Chronotype Questionnaire. The results showed that in men higher testosterone levels were related to eveningness and less sleep loss, whereas greater sleep loss was associated with lower levels of DHEA. In women, no associations between chronotype and levels of the analysed hormones were found. The results support the hypothesis that testosterone levels play a role in shaping eveningness. We further hypothesised that a possible cause of the higher secretion level of testosterone in men with the evening chronotype is a mechanism to offset the negative consequences of sleep loss.

Mothers' and fathers' joint profiles for testosterone and oxytocin in a small-scale fishing-farming community: Variation based on marital conflict and paternal contributions

INTRODUCTION

Testosterone and oxytocin are psychobiological mechanisms that interrelate with relationship quality between parents and the quantity and quality of parenting behaviors, thereby affecting child outcomes. Their joint production based on family dynamics has rarely been tested, particularly cross-culturally.

METHODS

We explored family function and salivary testosterone and oxytocin in mothers and fathers in a small-scale, fishing-farming society in Republic of the Congo. Fathers ranked one another in three domains of family life pertaining to the local cultural model of fatherhood.

RESULTS

Fathers who were viewed as better providers had relatively lower oxytocin and higher testosterone than men seen as poorer providers, who had lower testosterone and higher oxytocin. Fathers also had higher testosterone and lower oxytocin in marriages with more conflict, while those who had less marital conflict had reduced testosterone and higher oxytocin. In contrast, mothers in conflicted marriages showed the opposite profiles of relatively lower testosterone and higher oxytocin. Mothers had higher oxytocin and lower testosterone if fathers were uninvolved as direct caregivers, while mothers showed an opposing pattern for the two hormones if fathers were seen as involved with direct care.

CONCLUSIONS

These results shed new light on parents' dual oxytocin and testosterone profiles in a small-scale society setting and highlight the flexibility of human parental psychobiology when fathers' roles and functions within families differ across cultures.

Fathers: The interplay between testosterone levels and self-control in relation to parenting quality

In this study, we examined the potential interaction effect between fathers' basal testosterone levels and their ability to control their impulses in relation to their quality of parenting. Participants included 159 fathers and their preschoolers. Evening and morning salivary samples were analyzed with isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) to determine basal testosterone (T) levels. During a home-visit, fathers' self-control was measured with a computerized Go/NoGo task, and their sensitivity and respect for child autonomy was observed in a free-play session. We found that higher T levels in the evening were related to less respect for child autonomy, but only in fathers with low self-control. Further, higher T in the evening was related to more sensitive parenting, yet only in fathers with high self-control. These findings indicate that different aspects of fathers' quality of parenting are differently affected by the interaction between T and self-control. Further research is needed to clarify the interplay between fathers' neuro-endocrine system functioning and their trait characteristics in relation to the development of father-child relationships.

Motivations for a Casual or Occasional Sexual Encounter with a Man and/or Transgender Woman among Heterosexual Men: Toward a Better Understanding of Atypical Sexual Partnering

Little is known about the motivations for an occasional sexual encounter with a man or a transgender woman among heterosexual men. This study employed qualitative methods to better understand occasional atypical sexual partnering. Open-ended interviews were conducted with 31 heterosexual men who reported at least one sexual encounter with a man or a transgender woman in the previous 12 months. Using the principles of Grounded Theory, three themes emerged: Participants were motivated by (1) the easy, uncomplicated nature of a sexual encounter with a man and/or a trans woman that often circumvented the sexual politics of a typical male-female interaction and/or, (2) the sexual experimentation that took place with these partners; and/or, (3) the default nature of such encounters when a cisgender woman sexual partner was unavailable or perceived to be unattainable. These findings indicated that, among this sample of heterosexual men, the motivations for occasional atypical sexual partnering with a man or a transgender woman were varied, complex and could be multifaceted. Furthermore, these findings support prior studies that have demonstrated that sexual behavior can span beyond sexual identity.

Testosterone moderates the effects of social support on cardiovascular disease risk factors among older US men

OBJECTIVES

Social support positively affects health through pathways such as shaping intrapersonal emotional and psychological well-being. Lower testosterone often interrelates with psychological and behavioral orientations that are beneficial to participation in emotionally supportive relationships. Yet, little research has considered the ways in which testosterone may contribute to health outcomes related to emotional support.

METHODS

We draw on testosterone, social support data, and cardiovascular disease (CVD)-relevant indicators (inflammatory markers; blood pressure [BP]) from older men (n = 366) enrolled in the National Health and Nutrition Examination Survey, a US nationally representative study. We test whether men's testosterone moderates associations between emotional social support and markers related to CVD risk.

RESULTS

For men with relatively lower testosterone, higher levels of social support predicted lower white blood cell (WBC) counts, consistent with reduced inflammation. In contrast, men with higher testosterone exhibited elevated WBC counts with greater support. In a diverging pattern, men with lower testosterone had higher systolic and diastolic BP with higher support, whereas the slopes for systolic and diastolic BP, respectively, were comparatively flatter for men with higher levels of testosterone.

CONCLUSIONS

We suggest that our findings are theoretically consistent with the idea that testosterone helps shape intrapersonal and interpersonal experiences and perceptions of men's emotional support networks, thereby affecting the health implications of that support. The somewhat divergent results for WBC count vs BP highlight the need for inclusion of other neuroendocrine markers alongside testosterone as well as refined measures of perceived and received support.

With a little help from her friends (and family) part II: Non-maternal caregiving behavior and physiology in mammals

The diversity of competing frameworks for explaining the evolution of non-maternal care in mammals (Part I, this issue) reflects the vast range of behaviors and associated outcomes these theories attempt to subsume. Caretaking comprises a wide variety of behavioral domains, and is mediated by an equally large range of physiological systems. In Part II, we provide an overview of how non-maternal care in mammals is expressed, the ways in which it is regulated, and the many effects such care has on both recipients and caretakers. We also discuss the two primary ways in which closer integration of ultimate and proximate levels of explanation can be useful when addressing questions about non-maternal caretaking. Specifically, proximate mechanisms provide important functional clues, and are key to testing theory concerning evolutionary tradeoffs. Finally, we highlight a number of methodological and publication biases that currently shape the literature, which provide opportunities for knowledge advancement in this domain going forward. In this conclusion to our two-part introduction, we provide a broad survey of the behavior and physiology that the contributions to this special issue represent.