Evaluating the four most important salivary sex steroids during male puberty: testosterone best characterizes pubertal development

The digit ratio (2D:4D) and testosterone co-predict vertical jump performance in athletic boys: Evidence of organizational and activational effects of testosterone on physical fitness

The digit ratio (2D:4D) is a negative correlate of boy's physical fitness, and thought to arise from organizational effects of prenatal testosterone on different bodily systems. During human ontogeny, activational effects of testosterone on body size and strength offers another pathway to physical fitness. We tested these hypotheses by examining the organizational and activational effects of testosterone on vertical jump performance in athletic boys. Using a cross-sectional design, 173 boys (aged 9 to 18 years) were tested for standing height, body mass, body fat, fat-free mass, weekly training activity, training history, salivary testosterone and cortisol, R2D:4D, L2D:4D, and right-left 2D:4D (Dr-1), and vertical height in 3 different countermovement jump (CMJ) tests. A generalized additive model was employed to delineate age-related trajectories and predict CMJ performance. Our models yielded significant non-linear increases (or changes) in body size, current hormone concentration, training outcomes, and CMJ performance with chronological age. All 2D:4D measures were age invariant. The R2D:4D and testosterone were significant non-linear predictors of CMJ height with (R² = 66.2%) or without (R² = 54.3%) covariates, whereby a higher current testosterone concentration (up to a certain level) and a lower or higher R2D:4D were linked to better performance. The L2D:4D and Dr-1 had no predictive value. In conclusion, the R2D:4D and testosterone were co-predictors of CMJ height among athletic boys, with non-linear performance effects that differed in timing, tempo, and direction. Our findings confirm that testosterone can regulate a simple measure of boy's physical fitness through both an activational and organizational pathway.

Multidimensional and Intersectional Gender Identity and Sexual Attraction Patterns of Adolescents for Quantitative Research

To identify and compare gender identity and sexual attraction (GISA) patterns using a latent class analysis (LCA), questionnaire data from a cross-sectional study on social resilience in adolescence was conducted in 2020, using a sample of 785 Swiss seventh grade high school students. Following McCall’s complex intersectionality approach, we applied an intracategorical and intersectional approach to reshape, differentiate, and critique the existing binary, heteronormative GISA categorization. To empirically validate the detected classes according to content, we measured the participants’ psychological characteristics with measures of self-esteem, social competence, symptoms of anxiety and depression, dissociation, social desirability, and emotional styles, and related these measures to the respective GISA patterns the LCA detected. The results of our multistep LCA endorsed that heteronormatively binary gender identities are far too simplistic to fully illustrate adolescents’ differences and similarities where gender is concerned. Out of the subsample of n = 785 adolescents (375 identified as “assigned females” and 410 “assigned males”), three significant subgroups of multidimensional GISA patterns emerged for both assigned females and males where differences within the identified GISA groups were larger than those between traditional “boys” and “girls” overall. The LCA demonstrated that the six classes with GISA indicators could be described as low GISA diverse (cis/heterosexual), intermediate GISA diverse (gender identity diverse and/or sexual diverse), high GISA diverse (gender diverse/sexual diverse) for both assigned males and females thus showing that GISA and the psychological state according to gender variance is greater within groups of assigned females and assigned males than between these groups.

Dioxin exposure and sexual dimorphism of gaze behavior in prepubertal Vietnamese children living in Da Nang, a hot spot for dioxin contamination

Previous studies have reported that dioxin exposure alters sexual dimorphism of play behavior in pre-pubertal children. We aimed to investigate the effects of perinatal dioxin exposure, indicated by dioxins in breast milk, on sexual dimorphism of gaze behavior after adjusting for salivary testosterone (T). Participants were pre-pubertal children in a hot spot for dioxin contamination originating from herbicide spraying in Vietnam. We used eye tracking to assess gaze behavior in 172 children (100 boys and 72 girls) aged 8-9 years. Two sets of 15 pairs of pictures, one oriented towards boys and one oriented towards girls, containing 5 pairs of toy photos (non-biological stimuli) and 10 pairs of human line drawings (biological stimuli) were shown to all children. The total fixation duration for each picture was extracted using Tobii studio software and a feminine index of gaze behavior was defined as the ratio of the summed fixation duration for the girl- vs boy-oriented versions of each stimuli. When viewing non-biological stimuli, feminine index scores significantly increased with TCDD (β = 0.294) in girls only. For biological stimuli, however, feminine index scores significantly increased with TEQ-PCDD/Fs (β = 0.269) in boys and with TCDD in girls (β = 0.286). These associations were significant even after adjusting for salivary T levels, which were inversely associated with some dioxin congeners in girls. In addition, increased feminine index scores for biological stimuli were associated with lower cognitive scores for hand-movement and word-order tests in boys and for face-recognition tests in girls examined at 5 years of age. In conclusion, these results suggest that perinatal dioxin exposure may increase visual interest in girl-oriented objects through impairment of cognitive abilities in pre-pubertal Vietnamese children. PCDD congeners were associated with gaze behavior independently of T levels in boys, while this was only the case for TCDD levels in girls.

Field methods and strategies for assessing female reproductive functioning

A detailed understanding of female reproductive functioning is important to many disciplines including anthropology, evolutionary theory, demography, psychology, and biomedicine. In this article, I describe strategies and methods that have been used successfully in community-based studies of human reproduction, many in remote locales, to produce high quality biomarker data. These techniques are applicable to a wide range of research questions and populations, and to persons from adolescence through senescence. I give particular attention to the inherent challenges imposed by the cyclical and somewhat unpredictable nature of the hypothalamic-pituitary-ovarian axis including the necessity and difficulty of ascertaining the timing and occurrence of ovulation, the limits of different sampling regimes for capturing fluctuations in reproductive hormones, and the critical importance of recognizing and, when possible, reducing selection bias. I discuss the relative advantages and disadvantages of collecting saliva, urine, and dried blood spots, and describe some of the subtleties involved in collecting contamination-free samples. Once samples are collected, they must be stored in a manner that minimizes degradation; I describe techniques to keep samples cold even without access to electricity or dry ice. I also discuss various issues that should be considered during initial discussions with a laboratory and when samples are assayed by the laboratory. I include examples of techniques that have worked well in actual field studies, and examples of flawed analytical approaches that should be avoided. With these and other tools, even under technology-sparse conditions, researchers can investigate variability in human physiology across the breadth of human habitats.

Etiology and Clinical Profile of Patients with Tall Stature: A Single-Center Experience

BACKGROUND

There is no published literature on the profile of patients with tall stature (TS) from India. This study aimed to evaluate the etiological and clinical profile of patients with TS referred to our hospital.

MATERIALS AND METHODS

We performed a retrospective review of records of patients referred to us for evaluation of TS (January 2007 to March 2020). Relevant clinical, anthropometric, biochemical, and radiological data at presentation were recorded, and the final diagnosis reviewed.

RESULTS

The study included 16 subjects (6 boys, 10 girls) with a mean age at presentation of 13.2 ± 3.6 years. Most subjects were pubertal (n = 10) and belonged to the overweight or obese category (n = 10). The mean height and height standard deviation score (SDS) were 172.3 ± 20.3 cm and 3.6 ± 1.5, respectively, while mean mid-parental height (MPH) and MPH SDS were 168.8 ± 8.8 cm and 1.2 ± 0.9, respectively. The etiological diagnoses were familial TS (n = 9), acrogigantism (n = 3), obesity-related TS (n = 2), constitutional advancement of growth (n = 1), and Marfan syndrome (n = 1). The mean height SDS in subjects with acrogigantism was 6.4 ± 1.2 compared to 3.0 ± 0.6 in those with other etiologies of TS. Only one girl with familial TS and significantly increased predicted adult height (+4.56 SDS) opted for sex steroid therapy.

CONCLUSION

Familial TS is the most common diagnosis among patients referred for evaluation to our hospital. One should consider the possibility of acrogigantism in patients with growth acceleration, extreme TS, and markedly increased gap between height SDS and MPH SDS. Most patients with familial TS require reassurance and sex steroid therapy should be reserved for highly selected cases.