Digit Ratio 2D Research Articles

Digit ratio (2D:4D), laryngeal cancer and vocal fold leukoplakia

BackgroundTo date, there are no studies that have analyzed the possible influence of exposure to prenatal sex hormones on the risk of laryngeal cancer (LC) and premalignant laryngeal lesion—vocal fold leukoplakia (VFL). Digit ratio (2D:4D) is suggested to be a proxy of prenatal sex hormone exposure.ObjectiveTo examine 2D:4D in patients with LC and clarify if it could add to the verified risk factors in estimating the overall risk of LC.Methods511 subjects participated in the study. The study group included 269 patients: with LC (N = 114, 64 men) and VFL (N = 155, 116 men). Controls included 242 healthy individuals (66.40 ± 4.50 years (106 men)).ResultsPredictive models estimating the risk of VFL and LC in women, based solely on predictors like smoking and alcohol consumption had a lower area under the ROC curve (AUC) than the model with left 2D:4D. AUC for the model estimating the likelihood of VFL increased from 0.83 to 0.85, and for LC from 0.76 to 0.79.ConclusionsLow left 2D:4D may be associated with an increased risk of developing leukoplakia and laryngeal cancer in women. In the case of laryngeal cancer, left 2D:4D may serve as additional variable (to other known risk factors, such as smoking and/or alcohol consumption), which can improve cancer risk prediction.

A preliminary anthropometric study on second digit: Fourth digit (2D:4D) ratio and other hand dimensions for sex determination

Sex determination is one of the most important primary parameter in human identification. The development of forensic science in the world has provided identification tools and biometric systems for various identity cards. However, there is very little information available in Ghana on sex determination using Second digit: fourth Digit ratio (2D:4D), and hand dimensions. Therefore, the aim of the present study was to determine sex using 2D:4D, and hand dimensions. This quantitative cross-sectional study involved 100 (46 males and 54 females) undergraduate students of the University aged 17–26 years. Measurements of 2D:4D, and hand dimensions of participants were taken with a flatbed scanner (CanoScan LiDe 120) and resultant hand prints images were measured using the parallel dimension tool in Corel DRAW X7 application software. Statistical analysis was done using Statistical Package for Social Sciences (version 20.0). The average hand length, breadth and index were found to be greater in males than in females. The predominant hand index for the study was Dolichocheri (Long fingers with narrow small palm) and the least common was the Hyperdolichocheri (Very long fingers with narrow small palm). The 2D:4D showed sexual differences and the male participants recorded significantly higher values for the right hands but no significant difference for the left. A binary logistic regression analysis was done to determine the sex of the participants using 2D:4D, and hand dimensions. The significance of the study is that, it has provided additional data for forensic work in Ghana.

Dark Triad personality traits, second-to-forth digit ratio (2D:4D) and circulating testosterone and cortisol levels

IntroductionDark Triad (DT) personality traits (psychopathy, Machiavellianism, and narcissism) show sex differences and associations with hormones. Understanding aetiology may assist in mitigating the harm of these potentially adverse characteristics. Low second-to-fourth digit ratio (2D:4D) is hypothesised to be a marker of high prenatal testosterone exposure and may provide important information about organisational hormones. The aim of the present study was to measure Dark Triad and Big 5 personality traits in relation to digit ratio, salivary testosterone, and cortisol. MethodsA non-clinical sample (N = 268; 49.25% Female, age M25.20 ± 8.77 yrs) completed the Short Dark Triad and International Personality Inventory Pool - Mini. Afternoon saliva was analysed for testosterone and cortisol, and 2D:4D finger ratios were measured. ResultsMales scored higher on DT traits than females. Females scored higher on Big 5 agreeableness and neuroticism. Males had higher testosterone and cortisol levels and lower 2D:4D than females. Digit ratio correlated inversely with salivary testosterone, Machiavellianism, and psychopathy. Testosterone levels correlated positively with cortisol levels and psychopathy and negatively with agreeableness, neuroticism, and Machiavellianism. ConclusionsThese results provide indications that Machiavellianism and psychopathy (Dark Triad) traits, but not narcissism or Big 5 traits, are linked to markers of prenatal testosterone exposure. Results also replicate sex differences seen in 2D:4D digit ratios, with males having a shorter second-relative-to-forth finger. Links between circulating testosterone, digit ratios, cortisol and personality traits provide further information about potential biological bases of personality.

The association of prenatal amniotic sex hormones and digit ratio (2D:4D) in children aged 5 to 70 months: A longitudinal study.

The sex difference of the 2D:4D digit ratio (female > male)-a proposed marker for prenatal testosterone exposure-is well established. Studies suggest it already exists in utero and is of moderate effect size in adulthood. However, evidence for the claim that 2D:4D reflects prenatal androgen action is limited, and the sex difference may exhibit lability during childhood. In the present study, 244 mothers were recruited in the course of an amniocentesis examination (performed between gestational weeks 14 and 18). Prenatal testosterone (T) and estradiol (E) levels were determined from amniotic fluid for boys and girls. The majority (97.4%, n = 114) of available female T levels (n = 117) were found below the level of quantification. Therefore, only male amniotic fluid data (n = 117) could be included for the analysis of associations between amniotic sex hormones (T levels and T to E ratio (T/E)) and 2D:4D. The families were then invited to each of the five consecutive follow-ups (ages: 5, 9, 20, 40, and 70 months) where children's 2D:4D was measured for both hands. The alternative marker D[r-l] reflects the directional asymmetry of 2D:4D (right subtracted by left 2D:4D) and was subsequently calculated as an additional measure for prenatal T exposure. No significant correlations between amniotic T or the T/E ratio (measured between week 14 and 18 of gestation) with 2D:4D respectively D[r-l] were observed for any time point. There was a significant sex difference (females > males) and a significant age effect with moderate correlations of 2D:4D between time points. 2D:4D increased between 20 and 40 months and between 40 and 70 months of age. The findings raise questions regarding the applicability of 2D:4D as a marker for prenatal androgen action and are discussed in terms of the reliability of obtained digit ratio data as well as in terms of the developmental timing of amniocentesis.

Are the digit ratio (2D:4D) and hand grip strength related to Parkinson disease in elderly males?

BackgroundSex hormones affect the pathogenesis of Parkinson patients and it has been suggested that gender is the most important factor in the development and progression of Parkinson’s disease. Studies have shown that the second to fourth digit ratio (2D:4D) is affected by the prenatal testosterone and estrogen levels and can predict predisposition to disease. In addition, decreased muscle strength in people with Parkinson’s has been repeatedly reported. Hand grip strength (HGS) is a suitable measure to evaluate the musculoskeletal system among the elderly and it is considered as an indicator of the overall strength of the body. This study aimed at investigating the relationship between Parkinson’s disease and HGS and 2D:4D ratio.MethodsIn this study 117 elderly men with Parkinson disease (mean age of 61.66 ± 11.28 years) and 156 healthy control subjects (mean age of 61.86 ± 6.29 years) participated. After determining the level of disability of Parkinson patients by a neurologist (level of disability in the range of 1–4), anthropometric indices (height, weight, length of the second and fourth fingers) and maximum HGS were measured.ResultsAlthough 2D:4D ratios (right and left hand) of male patients with Parkinson’s disease were higher than those of healthy males, this difference was not statistically significant (P = 0.12, P = 0.40; respectively). Conversely, HGS for the right and left hands of Parkinson patients were significantly lower than those of healthy males (P = 0.02, P = 0.03; respectively). The results showed a significant negative relationship between Parkinson disease and the right and left HGS (R = -0.16, P = 0.005; R = -0.17, P = 0.003; respectively). Parkinson disease had no significant relationship with 2D:4D of the right hand, left hand, mean finger ratio and DR−L 2D:4D (P > 0.05). The regression results showed that the right and left HGS were not able to predict Parkinson disease (P = 0.25, P = 0.16; respectively).ConclusionWe concluded that HGS was negatively associated with the Parkinson disease, but conversely, 2D:4D may not be a valuable biomarker of elevated risk of Parkinson in elderly males.

Is There a Correlation between the Second-to-Four Digit Ratio (2D:4D) and Endometriosis? Results of a Case-Control Study.

The second-to-four digit ratio (2D:4D) has been proposed as a marker of prenatal hormonal exposure. It is suggested that prenatal exposure to androgens results in a shorter 2D:4D ratio, whereas a prenatal oestrogenic environment results in a longer one. In addition, previous research has shown an association between exposure to endocrine-disrupting chemicals and 2D:4D in animals and humans. On the endometriosis side, hypothetically, a longer 2D:4D ratio, reflecting a lower androgenic intrauterine milieu, could represent an indicator of the presence of the disease. In this light, we have designed a case-control study to compare 2D:4D measurements between women with and without endometriosis. Exclusion criteria included the presence of PCOS and previous trauma on the hand that could impact the measurement of the digit ratio. The 2D:4D ratio of the right hand was measured using a digital calliper. A total of 424 participants (endometriosis n = 212; controls n = 212) were recruited. The group of cases included 114 women with endometriomas and 98 patients with deep infiltrating endometriosis. The 2D:4D ratio was significantly higher in women with endometriosis compared to controls (p = 0.002). There is an association between a higher 2D:4D ratio and the presence of endometriosis. Our results support the hypothesis claiming potential influences of intrauterine hormonal and endocrine disruptors exposure on the onset of the disease.

High digit ratio (2D:4D) is associated with attack frequency and severity in hereditary angioedema patients

BackgroundHereditary angioedema (HAE) caused by a deficiency or dysfunction of the plasma protease C1-inhibitor is a rare autosomal-dominant disorder. We explored a possible correlation between the ratio of the second and fourth finger lengths (2D:4D) and the frequency of HEA attacks, and whether the ratio might predict laryngeal attack. MethodWe evaluated 35 HEA patients aged 19 to 66 years; 3 were subsequently excluded. The 2D:4D ratio was calculated by dividing the length of the second finger by that of the fourth finger of both hands. A structured clinical questionnaire exploring HAE course and treatment over the prior year was administered. ResultsOf the 32 participants, 56.25 % (n = 18) were female. Of them, those with high 2D:4D ratios suffered significantly more laryngeal attacks than others; 93.3% of patients with high 2D:4D ratios experienced ≥5 attacks annually, significantly more than those with low ratios. Among type 2 HEA patients, 75 % of those experiencing ≥5 attacks annually had high 2D:4D ratios; all patients with low 2D:4D ratios reported <5 attacks annually. These significant effects were found for right-hand 2D:4D ratios and not left-hand 2D:4D ratios. ConclusionThe data suggest that intrauterine sex hormone exposure, which affects the 2D:4D ratio, is significantly associated with HEA attack frequency and severity, and laryngeal edema.

An Exploratory Analysis on the 2D:4D Digit Ratio and Its Relationship with Social Responsiveness in Adults with Prader-Willi Syndrome.

Prader-Willi syndrome (PWS) is a genetic disorder produced by a lack of expression of paternally derived genes in the 15q11-13 region. Research has generally focused on its genetic and behavioral expression, but only a few studies have examined epigenetic influences. Prenatal testosterone or the maternal testosterone-to-estradiol ratio (MaTtEr) has been suggested to play an important role in the development of the 'social brain' during pregnancy. Some studies propose the 2D:4D digit ratio of the hand as an indirect MaTtEr measure. The relationship between social performance and MaTtEr has been studied in other neurodevelopmental conditions such as Autism Spectrum Disorder (ASD), but to our best knowledge, it has never been studied in PWS. Therefore, our study aims to clarify the possible existence of a relationship between social performance-as measured using the Social Responsiveness Scale (SRS)-and MaTtEr levels using the 2D:4D ratio. We found that, as a group, PWS individuals have shorter index and ring fingers than the control group, but no significant difference in the 2D:4D ratios. The 2D:4D ratio showed a correlation only with Restricted Interests and Repetitive Behavior Subscale, where a positive correlation only for male individuals with PWS was found. Considering only PWS with previous GH treatment during childhood/adolescence (PWS-GH), index and ring fingers did not show differences in length with the control group, but the 2D:4D ratio was significantly higher in the right or dominant hand compared to controls.

VARIATION OF DIGIT RATIO (2D:4D) IN ATHLETES AND DIFFERENCES WITH SPORTS GROUPS

El objetivo de este estudio fue determinar la variación y asociación del índice digital (2D: 4D) de los atletas de la mano derecha (2D: 4DR), mano izquierda (2D: 4DL), el valor medio (2D: 4DM) y la asimetría (2D: 4DA) en diferentes disciplinas deportivas. 1178 atletas de 25 disciplinas deportivas y 29 países se agruparon en cuatro categorías de deportes: Resistencia (n = 267, 22,7%), Potencia (n= 354, 30,1%), Balón (n= 344, 29,2%) y Combate (n= 213, 18,0%). La medición directa de la longitud de los dedos índice y anular de ambas manos se realizó utilizando calibradores digitales electrónicos de precisión. El índice digital se calculó para ambas manos. Los principales resultados fueron: Entre los grupos con la muestra agrupada por sexos, utilizando el ANOVA bidireccional, se encontraron diferencias significativas entre el grupo Balón en comparación a los tres grupos para 2D:4DL y 2D:4DM. En la submuestra de mujeres, el grupo Balón fue significativamente diferente del grupo Resistencia en 2D: 4DR y 2D: 4DM, p= .028, y p= .019, respectivamente; y de los grupos Fuerza y Combate en 2D:4DL y 2D:4DM (p&lt; .01). Dentro de la submuestra de hombres, el grupo Balón fue significativamente diferente de los otros tres grupos en 2D:4DL (p&lt; .01), de los grupos de Resistencia y Fuerza en 2D:4DM (p&lt; .05) y del grupo Combate en 2D:4DA (p= .015). Estos hallazgos sugieren que los deportes de pelota se diferencian de otros deportes en relación con 2D:4D; principalmente en 2D:4DL y 2D:4DM. La no diferencia en 2D:4D entre los grupos de Resistencia, Potencia y Combate apoya la hipótesis de que, además de la carrera de resistencia, otras habilidades están relacionadas con las proporciones de dígitos 2D:4D, estas habilidades pueden involucrar capacidades fisiológicas o características psicológicas. Estos resultados tienen varias implicaciones importantes en la detección y selección de talentos y ayudarán a tomar decisiones sobre los programas de formación.

No association between developmental instability as a general measure of stress and 2D:4D digit ratios in a non-western sample.

Random deviation from perfect symmetry of organisms is defined as fluctuating asymmetry. Fluctuating asymmetry is widely considered to be a marker of developmental instability, developmental noise and phenotypic quality at the population level. In this study, we investigated hypothesized relationship between 2D:4D digit ratios as a proxy measure of prenatal sex hormones and developmental instability levels in young adult humans. In the study, seven bilateral traits were measured for fluctuating asymmetry, as well as second and fourth digit lengths on both hands of 185 individuals, 87 men (mean age: 22.42 ± 3.37) and 97 women (mean age: 22.88 ± 3.87). The second digit length was divided by the fourth digit length and the resulting value was used as the digit ratio (2D:4D). Composite fluctuating asymmetry was calculated using five bilateral traits displaying fluctuating asymmetry. Only the right hand 2D:4D ratio is lower in men than in women. However, this difference disappears when the effect of digit lengths is controlled. Composite fluctuating asymmetry results reveal that men are more asymmetrical than women. There was no significant relationship between digit ratios and composite fluctuating asymmetry. In this study, the 2D:4D digit ratios appear to be influenced (at least in humans) by different digit lengths. This study also confirms previous studies that digit ratios as a proxy measure of exposure to either high testosterone or estrogen levels during early development does not appear to affect levels of developmental instability.

Investigating the correlation between 2D:4D finger digit ratios and attention gathering skills of 60–72 month-old children

BackgroundDigit ratio 2D:4D is used to follow children's development process and examine behaviours and abilities. AimThe aim of this study is to determine the correlation between the 2D:4D digit ratios of 60–72 month-old children and their attention gathering skills, as well as whether the 2D:4D digit ratio and attention gathering skills of children differ based on independent variables. MethodThe sample of the study, designed in the correlational survey model, consisted of a total of 112 children aged 60–72 months who were attending preschool education in Malatya province in Turkey. The data were analysed using SPSS packaged software. ResultsIt was determined that there was a positive low significant correlation between attention gathering skills and the right hand 2D:4D digit ratio in 60–72 month-old children. In addition to, no significant difference was found between the children's FTF-K scores and the right hand 2D:4D digit ratio in terms of the variable of mother's status of exercising, but there was a significant difference between their FTF-K scores and the left hand 2D:4D digit ratio in terms of the variable of the mother's status of exercising. ConclusionsThe findings of the study demonstrate the importance of the study for revealing clues about children's attention gathering/concentration levels from their early periods, and promoting their attention gathering skills and generally their cognitive development.

Digit ratio (2D:4D) and performance in non-elite male badminton players

Background: The second to fourth digit ratio (2D:4D ratio) is derived by dividing the length of the index finger (2D) by the length of the ring finger (4D). It has been considered as an index of how much the fetus is exposed to testosterone in utero. Research has suggested that high levels of testosterone are associated with low 2D:4D ratio. The relationship between 2D:4D ratio and physical performance is still an unexplored field in badminton players. Aims and Objectives: This study intends to assess the digit ratio 2D:4D in non-elite male badminton players in comparison to their sedentary controls. Materials and Methods: The study included 30 male badminton players in the age group of 19–23 years who were practicing badminton for more than 3 years and 30 age, body mass index-matched sedentary controls. The second and fourth finger measurements were taken from scanned printouts using Vernier calipers. Results: The 2D:4D ratio was significantly lower in the left hand of badminton players when compared to their controls (P = 0.0001). There was no significant difference in 2D:4D ratios of the right hand and 2D:4D (Δ r–l) between badminton players and controls. Conclusion: The findings in our study partly support the concept that 2D:4D ratio in an important parameter in selection of athletes. The reason for no difference in 2D:4D ratio and controls in the right hand could be due to the fact that badminton is a moderate intensity sport, and also, the study participants were non-elite players.

Readdressing pathophysiology of polycystic ovary syndromein post-COVID new normal era: A pilot study

Background: Polycystic ovary syndrome or PCOS is a complex endocrinopathy in women of reproductive age. The diversified expression pattern of this multigenic syndrome and its complex association with modulation in nutritional status, anthropometric indices, and biochemical parameters are still in puzzle. The COVID-19 pandemic has worsened the existing crosstalk by changing lifestyle toward more home confinement as well as sedentary. Aims and objectives: This study aimed to understand the effect of altered dietary patterns, anthropometric parameters like various adiposity indices, and biochemical parameters related to hyperandrogenism (HA) on the penetrance of PCOS in a new normal situation. Design: PCOS individuals (n= 50) and their age and gender (18–36 years)-matched healthy control (n= 50) were recruited in this study. Materials and methods: Food frequency questionnaire (FFQ), bioimpedance analyser (BIA), and biochemical assays were used to estimate different indices of the participants. Statistical analysis: IBM SPSS (Statistical Package for the Social Sciences), Version 20.0, Armonk, NY, was applied for analyzing quantitative variables (P&lt;0.05 andP&lt;0.01 indicate significance level). Results: Consumption of dietary fat (P&lt;0.01) and carbohydrates (P&lt;0.05) were significantly higher in PCOS individuals compared to the control one; 94% of PCOS patients were found to be under oligomenorrhea+polycysticovaries (O+PCO) category. The body fat content (P&lt;0.01 and 0.05) along with intrauterine androgen exposure(digit ratio-2D:4D,P= 0.000) were significantly higher and lower respectively, in PCOS individuals relative tothe control group. HA was highly prevalent in the PCOS group where 100% of them manifested alopecia, andsignificant (P&lt;0.01) correlation between free testosterone (free T) and free sex-hormone-binding-globulin (FSHBG)was also found. Low-density lipoprotein (LDL) was strongly associated with waist-to-height ratio (WHtR,P= 0.02)and body mass index (BMI,P= 0.041) in the same way as homeostatic model assessment for insulin resistance(HOMA-IR) with visceral adiposity index (VAI,P= 0.002) and lipid accumulation product (LAP,P= 0.014) index in PCOS individuals. Additionally, the triglyceride glucose (TyG) index was normally distributed (Kolmogorov–Smirnovtest = 0.20) in PCOS individuals. Conclusion: Abnormal alternation in dietary patterns, and anthropometric and biochemical indices could be promising indicators for early detection and better prognosis of this multifaceted syndrome.

Readdressing Pathophysiology of Polycystic Ovary Syndrome in Post-COVID New Normal Era - A Pilot Study

Background: Polycystic ovary syndrome or PCOS is a complex endocrinopathy in women of reproductive age. The diversified expression pattern of this polygenic syndrome and its complex association with modulation in nutritional status, anthropometric indices and biochemical parameters are still in puzzle. COVID-19 pandemic has worsened the existing crosstalk by changing the life style management towards more home confinement as well as sedentary. Aims and Objectives: It was aimed to understand the effect of altered dietary pattern, anthropometric parameters like various adiposity indices, biochemical parameters related to hyperandrogenism (HA) on penetrance of PCOS in new normal situation. Design: PCOS individuals (n=50) and their age and gender (18 to 36 years)‐matched healthy control (n=50) were recruited in this study. Materials and methods: Food frequency questionnaire (FFQ), bioimpedance analyzer (BIA) and biochemical assays were used to estimate different indices of the participants. Statistical Analysis: IBM SPSS (statistical package for the social sciences), Version 20.0, Armonk, NY, was applied for analyzing quantitative variables (P&lt;0.05 and P&lt;0.01 significance level). Results: Consumption of dietary fat (P&lt;0.01) and carbohydrates (P&lt;0.05) was significantly higher in PCOS individuals compared to the control one. 94% of PCOS patients were found to be fell under oligomenorrhea+polycystic ovaries (O+PCO) category. The body fat content (P&lt;0.01 and 0.05) along with androgen exposure (digit ratio-2D:4D, P=0.000) were significantly higher in PCOS individuals relative to control group. HA was highly prevalent in PCOS group where 100% of them manifested alopecia, and significant (P&lt;0.01) correlation between free testosterone (free T) and free sex-hormone-binding-globulin (free SHBG). Low-density lipoprotein (LDL) was strongly associated with waist-to-height ratio (WHtR, P=0.02) and body mass index (BMI, P=0.041) in the same way as homeostatic model assessment for insulin resistance (HOMA-IR) with visceral adiposity index (VAI, P=0.002) and lipid accumulation product (LAP, P=0.014) index in PCOS individuals. Additionally, triglyceride glucose (TyG) index was normally distributed (Kolmogorov-Smirnov test=0.20) in PCOS individuals. Conclusion: Abnormal alternation in dietary pattern, anthropometric and biochemical indices could be the promising indicators in early detection and better prognosis of this multifaceted syndrome.

Sex-moderated relationship between the 2D:4D ratio and circulating hormones in an adult Ghanaian population.

The second-to-fourth digit ratio (2D:4D) is the putative marker of prenatal hormone exposure. The 2D:4D ratio or the right-left difference (Dr-l) are said to be negative and positive correlates, respectively, of circulating testosterone and estrogen in both adult males and females. However, previous studies on the subject have reported mixed results. This study aimed to determine the sex-moderated relationship between the 2D:4D ratio and adult circulating testosterone, estradiol, testosterone-to-estradiol ratio and the free androgen index. This was a cross-sectional study from January to June 2021 at the University for Development Studies, Ghana. The study involved 62 participants (Female=28; Male=34), aged between 20 and 26 years. The right (2D:4DR), the left (2D:4DL), and their difference (Dr-l) were measured by computer-assisted analysis. Fasting venous samples were assayed for total testosterone (T), estradiol (E2 ), and sex hormone-binding globulin (SHBG) using ELISA. The free androgen index (FAI) was then calculated (T/SHBG) and the data were analyzed using moderated and/or weighted regression. Males had significantly higher T and FAI than females while females had significantly higher E2 than males, which were independent of age and body mass index (p < 0.001). There was a significant SEX*Dr-l interaction on FAI (p=0.007). The Dr-l correlated negatively with FAI in males but positively in females and accounted for about 94.0% of the variability of FAI in males (adjR2 =0.940) and only 0.2% in females (adjR2 =0.002). The 2D:4D ratio, a putative marker of prenatal hormone exposure, may have an impact on sex differences in adult free androgen index.

Investigation of the relationship between 2D:4D finger ratios and internet and smartphone addiction in middle school children

In humans, prenatal testosterone exposure affects a sexually dimorphic feature called the second-to-fourth digit ratio (2D:4D). Our research sought to better understand the connections among 2D:4D, Internet addiction (IA), and smartphone addiction (SPA) among middle school students. The study included 104 students aged between 10 and 14 years (mean age for girls: 11.3, the mean age for boys: 11.6), with 48 male and 56 female participants. Measurements of 2D:4D, hand length, and hand width were taken from the participants' hands. IA was assessed using the Young Internet Addiction Scale (YIAS), and SPA was assessed using the Smartphone Addiction Scale-Short Form (SAS-SF). In male participants, a negative correlation was found between the 2D:4D ratio and IA, while no correlation was observed in female participants. Both male and female participants showed a high correlation between IA and SPA. The study concludes that 2D:4D is an easily measurable and reliable marker for gender differentiation. It was found that male participants had higher levels of IA compared to female participants and that IA and SPA are strongly correlated in both genders.

Upper-Limb Disturbances in Female Patients with Poland Syndrome, including the Digit Ratio (2D:4D).

Poland syndrome (PS) is a rare congenital anomaly characterized by a variable clinical picture. Classic deformity consists of the unilateral hypoplasia or aplasia of the pectoralis major muscle and ipsilateral hand malformations. The aim of this study is to present disturbances in the development of upper limb in women with Poland syndrome (including digit ratio 2D:4D) in comparison to the healthy controls. The group of patients with Poland syndrome consisted of 36 women, while the control group consisted of 50 heathy women. Both upper limbs were measured anthropometrically. The length of all fingers and forearms were measured, and the digit ratio was calculated. In women with Poland syndrome, the length of digits 2 and 4 and the forearm were significantly higher on the nonaffected side than on the affected side. In addition, there were significant differences between the length of digits 2 and 4 and the forearm between patients and controls. In patients with Poland syndrome, the upper limb at the affected side is significantly different from the upper limb on the healthy side, mainly in the length of the forearm and digits. While examining the patient with Poland syndrome, we think it is essential to pay attention not only to hand anomalies but also to the development of whole upper limb. It may prove to be helpful in estimating the complete picture of Poland syndrome.

Parental Income and the Sexual Behavior of Their Adult Children: A Trivers-Willard Perspective.

Parental income is negatively and linearly related to the digit ratio (2D:4D; a proxy for prenatal sex steroids) of their children. Children of parents with high income are thought to be exposed to higher prenatal testosterone and develop lower 2D:4D. It is further hypothesized that 2D:4D relates to sexual orientation, although it is unclear whether the association is linear or curvilinear. Here, we consider patterns of parental income and its association with the sexual behavior of their adult children in a large online study (the BBC internet study). There were curvilinear relationships with parental income in male and female children. The highest frequencies of homosexuality and bisexuality were found in the lowest income group (bottom 25% of the population), the lowest frequencies in the income group representing the upper 50% of the population, and intermediate values in the other groups (low 50% and top 25% of the population). Parental income showed a U-shaped association with scores for same-sex attraction and an inverted U-shaped association with opposite-sex attraction. Thus, for the first time, we show that same-sex attraction is related to parental income. The curvilinear relationship between parental income and sexual behavior in their adult children may result from an association between very high fetal estrogen or testosterone and attraction to partners of the same sex. Among non-heterosexuals, and in both sexes, very high fetal estrogen may be associated with femme or submissive sexual roles, and very high fetal testosterone with butch and assertive sexual roles.

Is digit ratio (2D:4D) associated with a religious profession? An exploratory study on male Polish seminary students

Human females demonstrate higher religiosity than men in populations. Digit ratio (2D:4D), being a putative indicator of prenatal testosterone, is associated in varying degrees with characters that show sexual dimorphism. A small number of studies have indicated that religiosity may be associated with the biological basis of sex differences in humans. The objective of the present study was to ascertain whether 2D:4D in religiously oriented seminary students is different from individuals in other occupations. The study followed a cross-sectional design. Male participants of the study included 13 seminary students, 18 military chaplains and 91 control students from study courses relating to civil occupations. Lengths of second (2D) and fourth (4D) digits and their ratio (2D:4D) for each hand, height and weight were the variables and 2D:4D was the outcome measure. The results demonstrated that the seminary students had significantly higher 2D:4D than both the military chaplains and civil students. The military chaplains had the lowest 2D:4D. The study also revealed that the choice of religious occupation, and for that matter, religiosity, could be linked with the prenatal hormonal environment, particularly lower intrauterine testosterone compared to oestrogen.

The 2nd:4th digit ratio and shooting skill performance in Basketball Players

Abstract&#x0D; &#x0D; The aim of this study was to investigate the effect of 2d:4d digit ratio on shooting performance in basketball players. 30 male and 30 female basketball players who have been actively playing basketball for 3 years at the age of 15±04.1.69 participated in the study. Participants were asked to score 5 shots from the free throw line by scoring between 0 and 5 to determine their basketball shooting skill performance. To determine finger length, the second finger (2D) and fourth finger (4D) (Figure 3) were measured using a 0-150 mm (USA, Cocraft) Vernier digital caliper with an accuracy of 0.01 mm in millimeters (mm). In addition, the 20 Meter Shuttle Running Test was applied to measure the endurance of the participants. Independent sample T-Test and Pearson correlation test were used for statistical analysis. There was no significant difference in the participants' shot parameters, Shuttle Run Test and other 2D and 4D parameters (p&gt;0.05). There was a negative correlation between the 20 Meter Shuttle Running Test and the left hand 2d:4d variables of the participants (p0.05). It was found that there was no effect between 2D: 4D and aerobic performance and shooting in adolescent male and female basketball players. This result may be due to the age, training level and heterogeneity of the sample group.