Testosterone levels and their associations with lifetime number of opposite sex partners and remarriage in a large sample of American elderly men and women

Relatively rapid effects of testosterone on men's ratings of female attractiveness depend on relationship status and the attractiveness of stimulus faces

Attractiveness judgements influence desires to initiate and maintain romantic relationships. Testosterone also predicts relationship initiation and maintenance; such effects may be driven by the hormone's modulation of attractiveness judgements, but no studies have investigated causal (and situation-dependent) effects of the hormone on these judgements. Using a placebo-controlled cross-over design, our preregistered analyses revealed order- and relationship- dependent effects: single heterosexual men judged the women as more appealing when testosterone was administered first (and placebo second), but marginally less appealing when placebo was administered first (and testosterone second). In a more complex model incorporating the women's attractiveness (as rated by an independent set of observers), however, we show that testosterone increases the appeal of women -but this effect depends upon the men's relationship status and the women's attractiveness. In partnered men (n = 53) who tend to derogate attractive alternatives (by rating them as less appealing), testosterone countered this effect, boosting the appeal of these attractive alternatives. In single men (n = 53), conversely, testosterone increased the appeal of low-attractive women. These differential effects highlight the possibility of a newly discovered mechanism whereby testosterone promotes male sexual reproduction through different routes depending on relationship status, promoting partner up- rather than down-grading when partnered and reducing choosiness when single. Further, such effects were relatively rapid [within 85 (±5) minutes], suggesting a potential non-genomic mechanism of action.

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.

A meta-analysis of the association between male dimorphism and fitness outcomes in humans

Humans are sexually dimorphic: men and women differ in body build and composition, craniofacial structure, and voice pitch, likely mediated in part by developmental testosterone. Sexual selection hypotheses posit that, ancestrally, more 'masculine' men may have acquired more mates and/or sired more viable offspring. Thus far, however, evidence for either association is unclear. Here, we meta-analyze the relationships between six masculine traits and mating/reproductive outcomes (96 studies, 474 effects, N = 177,044). Voice pitch, height, and testosterone all predicted mating; however, strength/muscularity was the strongest and only consistent predictor of both mating and reproduction. Facial masculinity and digit ratios did not significantly predict either. There was no clear evidence for any effects of masculinity on offspring viability. Our findings support arguments that strength/muscularity may be sexually selected in humans, but cast doubt regarding selection for other forms of masculinity and highlight the need to increase tests of evolutionary hypotheses outside of industrialized populations.

Firstborn sex defines early childhood growth of subsequent siblings

Animal studies have shown that maternal resource allocation can be sex-biased in order to maximize reproductive success, yet this basic concept has not been investigated in humans. In this study, we explored relationships between maternal factors, offspring sex and prenatal and postnatal weight gain. Sex-specific regression models not only indicated that maternal ethnicity impacted male (n = 2456) and female (n = 1871) childrens postnatal weight gain differently but also that parity and mode of feeding influenced weight velocity of female (β ± s.e. = -0.31 ± 0.11 kg, p = 0.005; β ± s.e. = -0.37 ± 0.11 kg, p < 0.001) but not male offspring. Collectively, our findings imply that maternal resource allocation to consecutive offspring increases after a male firstborn. The absence of this finding in formula fed children suggests that this observation could be mediated by breast milk. Our results warrant further mechanistic and epidemiological studies to elucidate the role of breastfeeding on the programming of infant growth as well as of metabolic and cardiovascular diseases, with potential implications for tailoring infant formulae according to sex and birth order.

Effects of Male Facial Masculinity on Perceived Attractiveness

Studies suggest that high levels of masculinity in men can be a signal of 'better genes' as well as low parental investment. It is the trade-off between these two qualities that has led to the hypothesis that women's preferences for male masculinity are condition-dependent, yet, not all studies support this hypothesis. In addition, there is evidence that more average faces would be perceived as more attractive. Here we study the variation in masculinity preferences of a cohort of heterosexual women (n=769), using manipulated 3D faces of male subjects. We used linear mixed models to test for effects of various covariates such as relationship status, use of hormonal contraception, sociosexual orientation and self-perceived attractiveness on preference for masculinity. Our results show that women's sociosexual orientation has a positive correlation with masculinity preference while using hormonal contraception decreases this preference. None of the other covariates displayed any significant effect on masculinity preference. The initial level of masculinity of the faces (very low, low, average, high and very high) was also shown to affect this preference, where we found a significant preference for higher masculinity in the very low and average group, while no preference was found in the other groups. Our findings support the notion that condition-dependent variables have very small effects, if any, on women's preference for masculinity in men.

Testing strategic pluralism: The roles of attractiveness and competitive abilities to understand conditionality in men's short-term reproductive strategies

The decision to allocate time and energy to find multiple sexual partners or raise children is a fundamental reproductive trade-off. The Strategic Pluralism Hypothesis argues that human reproductive strategies are facultatively calibrated towards either investing in mating or parenting (or a mixture), according to the expression of features dependent on the individual's condition. This study seeks to test predictions derived from this hypothesis in a sample of 242 young men (M ± SD = 22.12 ± 3.08) from Chile's 5th Region (33֯ south latitude). Specifically, two predictions were considered that raise questions about the relationship between traits related to physical and psychological attractiveness (fluctuating facial asymmetry and self-perception of attractiveness) and competitive skills (baseline testosterone and self-perception of fighting ability) with short-term reproductive strategies. Our results indicate that psychological features related to the self-perception of physical attractiveness are related to short-term reproductive strategies. However, no evidence was found that fluctuating facial asymmetry, basal levels of testosterone and self-perception of fighting ability were related to short-term reproductive strategies. These results support the existing evidence of the importance of physical attractiveness in calibrating men's reproductive strategies but cast doubts about the role of fluctuating facial asymmetry. They also suggest that traits related to physical attractiveness, in comparison to competitive capabilities, play a more important role in calibrating men's short-term reproductive strategies.

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.

Network Connections and Salivary Testosterone Among Older U.S. Women: Social Modulation or Hormonal Causation?

OBJECTIVES

This study examined potentially bidirectional connections of older U.S. women's salivary testosterone with their social network connections.

METHODS

Data were from the 2005-2006 and 2010-2011 waves of the National Social Life, Health and Aging Project (NSHAP), a national probability sample of older U.S. adults. Autoregressive cross-lagged panel models tested linkages of women's testosterone with their social networks.

RESULTS

Consistent with recent biological theory suggesting social modulation of hormones, a higher kin proportion in one's egocentric (person-centered) network, arguably a stable compositional feature, negatively predicted women's testosterone levels. In contrast, findings for tie strength were consistent with hormonal regulation of women's sociality-with both perceived support from friends and family, and closeness to network members, negatively influenced by testosterone.

DISCUSSION

Rather than being a static and exogenous biological factor, older women's testosterone levels seem partly an outcome of their social context. Implications for sexual health and hormone therapy are discussed. However, this androgen also influences dimensions of their intimate networks critical to successful aging. Findings suggest the need for social scientists to engage with the neuroendocrine literature, which offers suggestions on linkages of hormones with specific network patterns.

The Influence of Endogenous Opioids on the Relationship between Testosterone and Romantic Bonding

The endogenous opioid system has received attention and extensive research for its effects on reward, pleasure, and pain. However, relative to other neurochemicals, such as oxytocin, vasopressin and dopamine, the function of opioids in regulating human attachment, sociosexuality, and other aspects of human sociality has not received much consideration. For example, nonapeptides (oxytocin and vasopressin) have been extensively studied in animals and humans for their possible roles in mother-offspring attachment, romantic attachment, fatherhood, and social cognition. Likewise, others have proposed models wherein oxytocin and vasopressin are moderators of the relationship between steroid hormones and human social behaviors. Recently, opioids have generated renewed interest in relation to social pain, and importantly, the brain opioid hypothesis of social attachment (BOTSA), which suggests that endogenous opioids are a key implementer in primate and human bonding, has received some support. Here we focus on romantic bonds by proposing that endogenous opioids are an important mechanism mediating reproductive trade-offs through their inhibitory effects on testosterone production.

Preliminary evidence that androgen signaling is correlated with men's everyday language

OBJECTIVES

Testosterone (T) has an integral, albeit complex, relationship with social behavior, especially in the domains of aggression and competition. However, examining this relationship in humans is challenging given the often covert and subtle nature of human aggression and status-seeking. The present study aimed to investigate whether T levels and genetic polymorphisms in the AR gene are associated with social behavior assessed via natural language use.

METHODS

We used unobtrusive, behavioral, real-world ambulatory assessments of men in partnered heterosexual relationships to examine the relationship between plasma T levels, variation in the androgen receptor (AR) gene, and spontaneous, everyday language in three interpersonal contexts: with romantic partners, with co-workers, and with their children.

RESULTS

Men's T levels were positively correlated with their use of achievement words with their children, and the number of AR CAG trinucleotide repeats was inversely correlated with their use of anger and reward words with their children. T levels were positively correlated with sexual language and with use of swear words in the presence of their partner, but not in the presence of co-workers or children.

CONCLUSIONS

Together, these results suggest that T may influence social behavior by increasing the frequency of words related to aggression, sexuality, and status, and that it may alter the quality of interactions with an intimate partner by amplifying emotions via swearing.

No Evidence for a Relationship Between Hair Testosterone Concentrations and 2D:4D Ratio or Risk Taking

Using a recently developed alternative assay procedure to measure hormone levels from hair samples, we examined the relationships between testosterone, cortisol, 2D:4D ratio, overconfidence and risk taking. A total of 162 (53 male) participants provided a 3 cm sample of hair, a scanned image of their right and left hands from which we determined 2D:4D ratios, and completed measures of overconfidence and behavioral risk taking. While our sample size for males was less than ideal, our results revealed no evidence for a relationship between hair testosterone concentrations, 2D:4D ratios and risk taking. No relationships with overconfidence emerged. Partially consistent with the Dual Hormone Hypothesis, we did find evidence for the interacting effect of testosterone and cortisol on risk taking but only in men. Hair testosterone concentrations were positively related to risk taking when levels of hair cortisol concentrations were low, in men. Our results lend support to the suggestion that endogenous testosterone and 2D:4D ratio are unrelated and might then exert diverging activating vs. organizing effects on behavior. Comparing our results to those reported in the existing literature we speculate that behavioral correlates of testosterone such as direct effects on risk taking may be more sensitive to state-based fluctuations than baseline levels of testosterone.

A review of human male field studies of hormones and behavioral reproductive effort

The purpose of this paper is to review field studies of human male hormones and reproductive behavior. We first discuss life history theory and related conceptual considerations. As illustrations, distinctive features of human male life histories such as coalitional aggression, long-term partnering and paternal care are noted, along with their relevance to overall reproductive effort and developmental plasticity. We address broad questions about what constitutes a human male field study of hormones and behavior, including the kinds of hormone and behavioral measures employed in existing studies. Turning to several sections of empirical review, we present and discuss evidence for links between prenatal and juvenile androgens and sexual attraction and aggression. This includes the proposal that adrenal androgens-DHEA and androstenedione-may play functional roles during juvenility as part of a life-stage specific system. We next review studies of adult male testosterone responses to competition, with these studies emphasizing men's involvement in individual and team sports. These studies show that men's testosterone responses differ with respect to variables such as playing home/away, winning/losing, and motivation. Field studies of human male hormones and sexual behavior also focus on testosterone, showing some evidence of patterned changes in men's testosterone to sexual activity. Moreover, life stage-specific changes in male androgens may structure age-related differences in sexual behavior, including decreases in sexual behavior with senescence. We overview the considerable body of research on male testosterone, partnerships and paternal care, noting the variation in social context and refinements in research design. A few field studies provide insight into relationships between partnering and paternal behavior and prolactin, oxytocin, and vasopressin. In the third section of the review, we discuss patterns, limitations and directions for future research. This includes discussion of conceptual and methodological issues future research might consider as well as opportunities for contributions in under-researched male life stages (juvenility, senescence) and hormones (e.g., vasopressin).

Testosterone and reproductive effort in male primates

Considerable evidence suggests that the steroid hormone testosterone mediates major life-history trade-offs in vertebrates, promoting mating effort at the expense of parenting effort or survival. Observations from a range of wild primates support the "Challenge Hypothesis," which posits that variation in male testosterone is more closely associated with aggressive mating competition than with reproductive physiology. In both seasonally and non-seasonally breeding species, males increase testosterone production primarily when competing for fecund females. In species where males compete to maintain long-term access to females, testosterone increases when males are threatened with losing access to females, rather than during mating periods. And when male status is linked to mating success, and dependent on aggression, high-ranking males normally maintain higher testosterone levels than subordinates, particularly when dominance hierarchies are unstable. Trade-offs between parenting effort and mating effort appear to be weak in most primates, because direct investment in the form of infant transport and provisioning is rare. Instead, infant protection is the primary form of paternal investment in the order. Testosterone does not inhibit this form of investment, which relies on male aggression. Testosterone has a wide range of effects in primates that plausibly function to support male competitive behavior. These include psychological effects related to dominance striving, analgesic effects, and effects on the development and maintenance of the armaments and adornments that males employ in mating competition.

Social Modulation or Hormonal Causation? Linkages of Testosterone with Sexual Activity and Relationship Quality in a Nationally Representative Longitudinal Sample of Older Adults

This study used population-representative longitudinal data from the 2005-2006 and 2010-2011 waves of the National Social Life, Health and Aging Project-a probability sample of US adults aged 57-85 at baseline (N = 650 women and 620 men)-to examine the causal direction in linkages of endogenous testosterone (T) with sexual activity and relationship quality. For both genders, our autoregressive effects indicated a large amount of temporal stability, not just in individual-level attributes (T, masturbation) but also dyadic ones (partnered sex, relationship quality)-indicating that a need for more nuanced theories of relational processes. Cross-lagged results suggested gender-specific effects-generally more consistent with sexual or relational modulation of T than with hormonal causation. Specifically, men's findings indicated their T might be elevated by their sexual (masturbatory) activity but not vice versa, although androgen levels did lower men's subsequent relationship quality. Women's T, in contrast, was negatively influenced not just by their higher relationship quality but also by their more frequent partnered sex-perhaps reflecting a changing function of sexual activity in late life.

Theoretical frameworks for human behavioral endocrinology

How can we best discover the ultimate, evolved functions of endocrine signals within the field of human behavioral endocrinology? Two related premises will guide my proposed answer. First, hormones typically have multiple, simultaneous effects distributed throughout the brain and body, such that in an abstract sense their prototypical function is the coordination of diverse outcomes. Second, coordinated output effects are often evolved, functional responses to specific eliciting conditions that cause increases or decreases in the relevant hormones. If we accept these premises, then a natural way to study hormones is to hypothesize and test how multiple eliciting conditions are mapped into coordinated output effects via hormonal signals. I will call these input-output mappings "theoretical frameworks." As examples, partial theoretical frameworks for gonadal hormones will be proposed, focusing on the signaling roles of testosterone in men and on estradiol and progesterone in women. Recent research on oxytocin in humans will also be considered as an example in which application of the theoretical framework approach could be especially helpful in making functional sense of the diverse array of findings associated with this hormone. The theoretical framework approach is not especially common in the current literature, with many theories having eschewed explicit consideration of input-output mappings in favor of parsimony-based arguments that attempt to find the one main thing that a hormone does with respect to psychology or behavior. I will argue that these parsimony-based models have many shortcomings, and conclude that the construction and testing of theoretical frameworks provides a better means of discovering the evolved functions of human endocrine signals.

Exogenous testosterone increases men's perceptions of their own physical dominance

Men's testosterone is associated with several constructs that are linked to dominance rank, such as risk-taking, mating success, and aggression. However, no study has directly tested the relationship between men's self-perceived dominance and testosterone using an experimental design. We employed a within-subjects, double-blind, placebo-controlled paradigm to assess whether testosterone influences men's self-perceived dominance. Exogenous testosterone or a placebo was administered to healthy adult men and self-perceptions of physical dominance were subsequently assessed by having participants select what they believed to be their true face from an array of images digitally manipulated in masculinity. Men picked a more masculine version of their own face after testosterone versus placebo--an effect that was particularly pronounced among men with relatively low baseline testosterone. These findings indicate that a single administration of testosterone can rapidly modulate men's perceptions of their own physical dominance, which may explain links between testosterone and dominance-related behaviors.

Is Hypersexuality Dimensional or Categorical? Evidence From Male and Female College Samples

The recent attempt to introduce hypersexual disorder into the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), has increased empirical scrutiny of the construct. Consensus on its definition and underlying structure remains elusive. Whereas some conceptualizations favor a categorical latent structure, others speculate that hypersexual behavior is dimensional. Research on the latent structure of hypersexual behavior, however, has been sparse. This is unfortunate, because determination of the latent structure can contribute to more accurate assessment, diagnosis, and understanding of etiological process. To date the only study on hypersexuality's latent structure found consistent evidence of a dimensional structure for males but less clear results for females. In the present study the Multidimensional Inventory of Development, Sex, and Aggression (MIDSA), a self-report, contingency-based inventory, was administered to 1,146 college students. Four indices of hypersexual behavior and six indices of sexual compulsivity were analyzed, using three taxometric methods (mean above minus below a cut [MAMBAC], maximum covariance [MAXCOV], and latent mode factor analysis [L-Mode]). Evidence supported a dimensional latent structure for hypersexuality in male and female samples. Future assessments of hypersexuality must focus on adequate reliability and discriminant validity across the continuum of sexual behavior rather than on attempts to differentiate between arbitrarily developed diagnostic categorizations.

Fulfilling desire: evidence for negative feedback between men's testosterone, sociosexual psychology, and sexual partner number

Across human societies and many nonhuman animals, males have greater interest in uncommitted sex (more unrestricted sociosexuality) than do females. Testosterone shows positive associations with male-typical sociosexual behavior in nonhuman animals. Yet, it remains unclear whether the human sex difference in sociosexual psychology (attitudes and desires) is mediated by testosterone, whether any relationships between testosterone and sociosexuality differ between men and women, and what the nature of these possible relationships might be. In studies to resolve these questions, we examined relationships between salivary testosterone concentrations and sociosexual psychology and behavior in men and women. We measured testosterone in all men in our sample, but only in those women taking oral contraception (OC-using women) in order to reduce the influence of ovulatory cycle variation in ovarian hormone production. We found that OC-using women did not differ from normally-ovulating women in sociosexual psychology or behavior, but that circulating testosterone mediated the sex difference in human sociosexuality and predicted sociosexual psychology in men but not OC-using women. Moreover, when sociosexual psychology was controlled, men's sociosexual behavior (number of sexual partners) was negatively related to testosterone, suggesting that testosterone drives sociosexual psychology in men and is inhibited when those desires are fulfilled. This more complex relationship between androgens and male sexuality may reconcile some conflicting prior reports.

Conservative Christianity, partnership, hormones, and sex in late life

Using nationally representative data from the 2005-2006 U.S. National Social Life, Health, and Aging Project, this study queried relationship, sexual, and sex hormone patterns among married evangelical women and men aged 57-85, relative to those in other religions. Results suggested that despite potentially more unequal gender roles, evangelical older women may have better marital quality, perhaps due to the recent transformation of their male counterparts into authoritative, yet-supportive, "soft patriarchs." Correspondingly, these women, especially those with greater subjective religiosity or more support from a spouse, reported consistently better sexual outcomes than their counterparts in other religions. In addition, they also had lower estradiol, whether due to psychobiological effects of their better relationships or self-selection of those with differential hormone levels into particular partnership patterns. While older men in these communities also experienced more satisfactory marriages, and had lower androgens (testosterone, DHEA), their relational assets were less uniformly matched by better sexual outcomes, perhaps reflecting a gender disparity in the linkage between these factors.

Is preference for ovulatory female's faces associated with men's testosterone levels?

Women's ovulation is perceivable with different senses. Already subtle face shape differences are enough to trigger men's preference for the ovulatory female. The aim of the present study is to investigate if men's testosterone level can be linked to their preference for the ovulatory female. Thirty-nine heterosexual participants were shown face pairs of which one of them was transformed to the shape of a prototype face of a woman in her luteal cycle phase and the other was transformed to the shape of a prototype face of an ovulatory woman. Participants were asked to choose the face which they perceived as being more attractive (attractiveness task), or the woman with whom they would have better chances to get a date (dating task). In both tasks, the ovulatory female was chosen more often. Testosterone was not predictive for the chosen face; regardless of testosterone level men preferred the ovulatory woman. However testosterone predicted how confident the men were with their choice. Men with lower testosterone levels were more confident with their choice than men with higher testosterone levels.

Menstrual cycle effects on attitudes toward romantic kissing

Hormonal changes associated with the human menstrual cycle have been previously found to affect female mate preference, whereby women in the late follicular phase of their cycle (i.e., at higher risk of conception) prefer males displaying putative signals of underlying genetic fitness. Past research also suggests that romantic kissing is utilized in human mating contexts to assess potential mating partners. The current study examined whether women in their late follicular cycle phase place greater value on kissing at times when it might help serve mate assessment functions. Using an international online questionnaire, results showed that women in the follicular phase of their menstrual cycle felt that kissing was more important at initial stages of a relationship than women in the luteal phase of their cycle. Furthermore, it was found that estimated progesterone levels were a significant negative predictor for these ratings.

Early follicular testosterone level predicts preference for masculinity in male faces - but not for women taking hormonal contraception

It has been shown that women's preference for masculinity in male faces changes across the menstrual cycle. Preference for masculinity is stronger when conception probability is high than when it is low. These findings have been linked to cyclic fluctuations of hormone levels. The purpose of the present study is to further investigate the link between gonadal steroids (i.e. testosterone, estradiol, and progesterone) and masculinity preference in women, while holding the cycle phase constant. Sixty-two female participants were tested in their early follicular cycle phase, when conception probability is low. Participants were shown face pairs and where asked to choose the more attractive face. Face pairs consisted of a masculinized and feminized version of the same face. For naturally cycling women we found a positive relationship between saliva testosterone levels and masculinity preference, but there was no link between any hormones and masculinity preference for women taking hormonal contraception. We conclude that in naturally cycling women early follicular testosterone levels are associated with masculinity preference. However, these hormonal links were not found for women with artificially modified hormonal levels, that is, for women taking hormonal contraception.

Do testosterone declines during the transition to marriage and fatherhood relate to men's sexual behavior? Evidence from the Philippines

Testosterone (T) is thought to help facilitate trade-offs between mating and parenting in humans. Across diverse cultural settings married men and fathers have lower T than other men and couples' sexual activity often declines during the first years of marriage and after having children. It is unknown whether these behavioral and hormonal changes are related. Here we use longitudinal data from a large study in the Philippines (n=433) to test this model. We show that among unmarried non-fathers at baseline (n=153; age: 21.5 ± 0.3 years) who became newly married new fathers by follow-up (4.5 years later), those who experienced less pronounced longitudinal declines in T reported more frequent intercourse with their partners at follow-up (p<0.01) compared to men with larger declines in T. Controlling for duration of marriage, findings were similar for men transitioning from unmarried to married (without children) (p<0.05). Men who remained unmarried and childless throughout the study period did not show similar T-sexual activity outcomes. Among newly married new fathers, subjects who had frequent intercourse both before and after the transition to married fatherhood had more modest declines in T compared to peers who had less frequent sex (p<0.001). Our findings are generally consistent with theoretical expectations and cross-species empirical observations regarding the role of T in male life history trade-offs, particularly in species with bi-parental care, and add to evidence that T and sexual activity have bidirectional relationships in human males.

Race differentials in partnering patterns among older U.S. men: influence of androgens or religious participation?

Using nationally representative data from the 2005-2006 U.S. National Social Life, Health, and Aging Project, this study queried race differences in older men's polyamorous and casual sex, as well as stratification of these patterns by endogenous androgens (testosterone and dehydroepiandrosterone) and by regular religious participation. Results suggested that despite their respective prominence in the biomedical and sociological literatures on sex, neither "bottom up" hormonal influences nor "top down" religious social control were major structuring factors for greater lifetime as well as current likelihood of these behaviors among older Black than White men. Androgens were higher among the former, but did not seem to drive these race patterns. Regular church attendance--while negatively associated with non-monogamous and prolific partnering, and hence possibly a social control mechanism among all men--played only a weak role in moderating ethnic variations in these behaviors. It is speculated that these differences may instead be driven by unexamined current or early factors, including, perhaps, Black men's greater exposure to sexualizing processes in adolescence that, even in late life, may outweigh more temporally-proximal influences.

Testosterone and temperament traits in men: Longitudinal analysis

Testosterone is the main male hormone that has been associated with various behavioral traits in humans and other animals. We investigated whether levels of total testosterone, free testosterone, and sex hormone binding globulin were associated with temperament traits in a population-based sample of Finnish men at two measurement times taken 6 years apart (n=686 in year 2001, n=727 in year 2007). Temperament was assessed using the Temperament and Character Inventory that consists of four temperament traits: novelty seeking, harm avoidance, reward dependence, and persistence. Higher levels of total and free testosterone were associated with higher novelty seeking (standardized B=0.103, p<0.001). This association was also observed in a longitudinal within-person analysis (B=0.084, p=0.008), suggesting that the association is not confounded by stable between-individual differences in other characteristics. Within-individual variation in total testosterone was associated with higher reward dependence, and higher levels of free testosterone were marginally associated with higher reward dependence. Reward dependence reflects the importance of social rewards to an individual. These results provide additional evidence for the stable and time-varying associations between testosterone and temperament in humans.

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

Largely based on pre-theory that ties high testosterone (T) to masculinity, and low T to femininity, high T is mainly studied in relation to aggression, mating, sexuality, and challenge, and low T with parenting. Evidence, however, fails to support this, and the social variability in T is better accounted for by a competition-nurturance trade-off as per the Steroid/Peptide Theory of Social Bonds (van Anders et al., 2011). Four key domains are discussed: adult-infant interactions, sexual desire, sexual behavior, and partnering. Empirical engagements with gender/sex are shown to lead to important insights over assumptions about masculinity-femininity. Humans are discussed within a comparative framework that attends to cross-species principles informed by human insights alongside human-specific particularities like social constructions, which are critical to evolutionary understandings of the social role of T. This paper thus integrates seemingly orthogonal perspectives to allow for transformative approaches to an empirically-supported social phenomenology of T.

Individual differences in mate poaching: an examination of hormonal, dispositional, and behavioral mate-value traits

The personality and hormonal correlates of mate poaching (attempting to steal another person's partner away) and of the target of the seducer (the mate poached) were examined in a sample 154 undergraduate university students (91 females; 63 males). Thirteen variables were modeled into two regression equations to predict and profile mate poachers and the mate poached. Findings revealed that (1) male mate poachers were better looking and had higher cortisol levels, lower levels of testosterone, and reported being higher on self-esteem, cold affect, and criminal tendencies and (2) female mate poachers and targets of mate poachers reported being more physically attractive, as did male targets of mate poachers. Sex differences in the context of mate poaching attraction as well as the characteristics of those who are successful in their attempts to lure away another person's romantic partner were discussed.

Testosterone levels are negatively associated with fatherhood [corrected] in males, but positively related to offspring count in fathers

Variation in testosterone (T) is thought to affect the allocation of effort between reproductive and parenting strategies. Here, using a large sample of elderly American men (n = 754) and women (n = 669) we examined the relationship between T and self-reported parenthood, as well as the relationship between T and number of reported children. Results supported previous findings from the literature, showing that fathers had lower T levels than men who report no children. Furthermore, we found that among fathers T levels were positively associated with the number of children a man reports close to the end of his lifespan. Results were maintained when controlling for a number of relevant factors such as time of T sampling, participant age, educational attainment, BMI, marital status and reported number of sex partners. In contrast, T was not associated with either motherhood or the number of children women had, suggesting that, at least in this sample, T does not influence the allocation of effort between reproductive and parenting strategies among women. Findings from this study contribute to the growing body of literature suggesting that, among men, pair bonding and paternal care are associated with lower T levels, while searching and acquiring sex partners is associated with higher T levels.

Sex Differences in Risk Taking Behavior among Dutch Cyclists

The majority of research examining sex differences in risk-taking behavior focuses on overt physical risk measures in which failed risk attempts may result in serious injury or death. The present research describes sex differences in patterns of risk taking in day-to-day behavior among Dutch cyclists. Through three observational studies we test sex differences in risk taking in situations of financial risk (fines for failing to use bike lights, Study 1), theft risk (bike locking behavior, Study 2) as well as physical risk (risky maneuvers, Study 3). Results corroborate previous findings by showing that across these domains men are more inclined to take risks than women. We discuss how these findings might be used in an applied context.

Does cosleeping contribute to lower testosterone levels in fathers? Evidence from the Philippines

Because cross-species evidence suggests that high testosterone (T) may interfere with paternal investment, the relationships between men's transition to parenting and changes in their T are of growing interest. Studies of human males suggest that fathers who provide childcare often have lower T than uninvolved fathers, but no studies to date have evaluated how nighttime sleep proximity between fathers and their offspring may affect T. Using data collected in 2005 and 2009 from a sample of men (n = 362; age 26.0 ± 0.3 years in 2009) residing in metropolitan Cebu, Philippines, we evaluated fathers' T based on whether they slept on the same surface as their children (same surface cosleepers), slept on a different surface but in the same room (roomsharers), or slept separately from their children (solitary sleepers). A large majority (92%) of fathers in this sample reported practicing same surface cosleeping. Compared to fathers who slept solitarily, same surface cosleeping fathers had significantly lower evening (PM) T and also showed a greater diurnal decline in T from waking to evening (both p<0.05). Among men who were not fathers at baseline (2005), fathers who were cosleepers at follow-up (2009) experienced a significantly greater longitudinal decline in PM T over the 4.5-year study period (p<0.01) compared to solitary sleeping fathers. Among these same men, baseline T did not predict fathers' sleeping arrangements at follow-up (p>0.2). These results are consistent with previous findings indicating that daytime father-child interaction contributes to lower T among fathers. Our findings specifically suggest that close sleep proximity between fathers and their offspring results in greater longitudinal decreases in T as men transition to fatherhood and lower PM T overall compared to solitary sleeping fathers.

Longitudinal evidence that fatherhood decreases testosterone in human males

In species in which males care for young, testosterone (T) is often high during mating periods but then declines to allow for caregiving of resulting offspring. This model may apply to human males, but past human studies of T and fatherhood have been cross-sectional, making it unclear whether fatherhood suppresses T or if men with lower T are more likely to become fathers. Here, we use a large representative study in the Philippines (n = 624) to show that among single nonfathers at baseline (2005) (21.5 ± 0.3 y), men with high waking T were more likely to become partnered fathers by the time of follow-up 4.5 y later (P < 0.05). Men who became partnered fathers then experienced large declines in waking (median: -26%) and evening (median: -34%) T, which were significantly greater than declines in single nonfathers (P < 0.001). Consistent with the hypothesis that child interaction suppresses T, fathers reporting 3 h or more of daily childcare had lower T at follow-up compared with fathers not involved in care (P < 0.05). Using longitudinal data, these findings show that T and reproductive strategy have bidirectional relationships in human males, with high T predicting subsequent mating success but then declining rapidly after men become fathers. Our findings suggest that T mediates tradeoffs between mating and parenting in humans, as seen in other species in which fathers care for young. They also highlight one likely explanation for previously observed health disparities between partnered fathers and single men.