The development of sex differences in digital formula from infancy in the Fels Longitudinal Study

McIntyre, Matthew H.; Ellison, Peter T.; Lieberman, Daniel E.; Demerath, Ellen W.; Towne, Bradford

doi:10.1098/rspb.2005.3100

Cited by 217 publications

(228 citation statements)

References 27 publications

Supporting

Mentioning

189

Contrasting

Unclassified

Order By: Relevance

“…As expected, males had lower mean 2D:4D ratio than females, but like previous authors [2,14] we found that the difference is subtle and there is a large overlap of 2D:4D distributions between sexes (Fig. 1).…”

Section: Discussionsupporting

confidence: 46%

“…Two longitudinal studies [14,15] provided solid evidence that the digit ratios increase from infancy to adulthood, especially between ages one and five, although the magnitude of the change is small. Similarly, Galis et al [16] working with 327 deceased human fetuses (14 to 42 weeks old) reported that the prenatal 2D:4D in both sexes was lower than has been reported for children and adults, suggesting that it may increase after birth.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Digit ratio (2D:4D) in newborns: Influences of prenatal testosterone and maternal environment

Ventura

Gomes

Pita

et al. 2013

Early Human Development

158

171

View full text Add to dashboard Cite

Introduction: The 2D:4D digit ratio is sexually-dimorphic, probably due to testosterone action through the perinatal period. We characterize the 2D:4D ratio in newborn (NB) infants, in between the pre-and postnatal surges of testosterone, and relate it to the mother's 2D:4D and to testosterone levels in the amniotic fluid (AF). Subjects and methods: Testosterone was assayed in samples of maternal plasma and AF collected at amniocentesis. Shortly after birth, 106 NBs and their mothers were measured for 2D:4D ratio. Results: NB males had lower mean 2D:4D ratios than females but this dimorphism was significant only for the left hand (males: 0.927; females: 0.950; p =0.004). Mothers who had sons had lower 2D:4D ratios than those who had daughters and the mother's 2D:4D were higher than those of NBs regardless of sex. Both hands of NB females were negatively correlated with AF testosterone and positively correlated with the mother's 2D:4D, but males showed no significant associations. Maternal plasma testosterone also showed a negative weak correlation with NB's digit ratio in both sexes. Conclusions: Sexual dimorphism at birth was only significant for the left hand, in contrast with reports of greater right hand dimorphism, suggesting that postnatal testosterone is determinant for 2D:4D stabilization. The lower 2D:4D ratios in mothers who had sons support claims that hormone levels in parents are influential for determining their children's sex. NB female's digit ratio, but not males', was associated to the level of AF testosterone. The mother's 2D:4D ratios were positively correlated with their daughters' 2D:4D, but the same was not observed for male NBs, suggesting that prenatal testosterone levels in male fetus lead their 2D:4D ratios to stray from their mothers' with high individual variability.

show abstract

Section: Discussionsupporting

confidence: 46%

Section: Introductionmentioning

confidence: 99%

Digit ratio (2D:4D) in newborns: Influences of prenatal testosterone and maternal environment

Ventura

Gomes

Pita

et al. 2013

Early Human Development

158

171

View full text Add to dashboard Cite

show abstract

“…Other investigators have used image analysis to determine 2D:4D from images obtained from flatbed scanners (Bailey and Hurd, 2005;de Bruin et al, 2006;McFadden and Shubel, 2002), radiographs (McIntyre et al, 2005, and digital photographs (Honekopp et al, 2006a;Pokrywka et al, 2005). Bailey and Hurd (2005) showed good intraobserver reliability when a single observer measured finger lengths in 10 subjects using computer-assisted image analysis on hand scans while McFadden and Shubel (2002) showed good interobserver reliability when three observers measured finger lengths using similar computer-based calipers on scanned images of the hand.…”

Section: Discussionmentioning

confidence: 99%

Digit ratios (2D:4D) determined by computer‐assisted analysis are more reliable than those using physical measurements, photocopies, and printed scans

Allaway

Bloski

Pierson

et al. 2009

American J Hum Biol

111

View full text Add to dashboard Cite

Prenatal androgens influence the second to fourth digit ratio (2D:4D) of hands with men having lower ratios than women. Numerous methods are used to assess 2D:4D including, physical measurements with calipers, and measurements made from photocopies, scanned images, digital photographs, radiographs, and scaled tubes. Although each method appears relatively reliable, agreement upon a gold standard is necessary to better explore the putative effects of prenatal androgens. Our objective was to assess the level of intra and interobserver reliability when evaluating 2D:4D using four techniques: (1) physical measurements, (2) photocopies, (3) printed scanned images, and (4) computer-assisted image analysis. Physical measurements, photocopies, and printed scanned images were measured with Vernier calipers. Scanned images were also measured with computer-based calipers. Measurements were made in 30 men and 30 women at two different time points, by three experienced observers. Intraclass correlation coefficients were used to assess the level of reliability. Intraobserver reliability was best for computer-assisted (0.957), followed by photocopies (0.939), physical measurements (0.925), and printed scans (0.842; P = 0.015). Interobserver reliability was also greatest for computer-assisted (0.892), followed by photocopies (0.858), physical measurements (0.795), and printed scans (0.761; P = 0.001). Mean 2D:4D from physical measurements were higher than all other techniques (P < 0.0001). Digit ratios determined from computer-assisted, physical measurements, and printed scans were more reliable in men than women (P = 0.009, P = 0.017, and P = 0.012, respectively).In summary, 2D:4D determined from computer-assisted analysis yielded the most accurate and consistent measurements among observers. Investigations of 2D:4D should use computer-assisted measurements over alternate methods whenever possible.Prenatal androgen exposure influences development of the fingers and leads to distinct differences in hand patterns among men and women. In general, the ratio between the second (2D = index finger) and fourth (4D = ring finger) digits in men is lower than that observed in women (Lutchmaya et al., 2004;Manning et al., 1998). Anatomical evidence of prenatal androgen exposure has gained significance in recent times because there is growing evidence in animal models that adult traits and behaviors including, disease susceptibility may be programmed during fetal development (Abbott et al., 2006;Manikkam et al., 2004 Manning and Bundred, 2000;Robinson, 2006). Previous studies in humans have shown low digit ratios (2D:4D) to be associated with a variety of traits including, enhanced visual spatial ability (Burton et al., 2005;van Anders and Hampson, 2005), increased athleticism (Honekopp et al., 2006a), female homosexuality (Brown et al., 2002;Hall and Love, 2003;Kraemer et al., 2006;Williams et al., 2000), decreased susceptibility to coronary artery disease (Fink et al., 2003;Manning and Bundred, 2000), and greater fertility potent...

show abstract

“…While the prenatal origin of digit ratios has been established conclusively, there is suggestive evidence that-at least in humans-sex hormones levels in early infancy may further contribute to individual and sex differences in relative finger length (Galis et al 2010;Knickmeyer et al 2011). In childhood, sex differences in 2D:4D can be reliably detected from at least 5 years of age, though they are somewhat smaller than those observed in adults (McIntyre et al 2005;McIntyre et al 2006;Trivers et al 2006).…”

Section: The 2d:4d Digit Ratio As a Marker Of Early Exposure To Sex Hmentioning

confidence: 92%

“…The gold standard for digit ratio measurement is based on bone length estimation from X-rays, CT scans, or similar methods (e.g., McIntyre et al 2005); however, most studies in humans measure digit ratios indirectly on the skin surface, either with a caliper or from hand scans or photocopies. While indirect methods are considerably more practical, they increase the measurement error associated with 2D:4D estimation and further weaken the correlation with early hormonal exposure.…”

Section: The 2d:4d Digit Ratio As a Marker Of Early Exposure To Sex Hmentioning

confidence: 99%

Digit Ratio (2D:4D) and Attachment Styles in Middle Childhood: Indirect Evidence for an Organizational Effect of Sex Hormones

Giudice

Angeleri

2015

Adaptive Human Behavior and Physiology

View full text Add to dashboard Cite

Sex differences in attachment are absent during infancy and early childhood, emerge in middle childhood with self-reports and doll-play tasks, and persist into adulthood, when they are most reliably detected in romantic attachment styles. In our previous work, we hypothesized that sex differences in attachment develop under the influence of adrenal androgens during the transition form early to middle childhood, following activation of hormone-sensitive neural pathways organized by prenatal and early postnatal exposure to sex hormones. In this study we tested the association between the right-hand 2D:4D digit ratio (a marker of early exposure to androgens and estrogen) and sexually differentiated dimensions of attachment in middle childhood assessed with the Coping Strategies Questionnaire (CSQ). In a sample of 285 Italian children aged 8-10 years, females scored lower in avoidance and higher in preoccupation, while no significant sex differences were observed in felt security. Consistent with our predictions, higher (feminized) digit ratios were significantly associated with lower avoidance and higher preoccupation scores in both males and females. In contrast, there was no significant association between digit ratio and felt security in either sex. These results corroborate the hypothesis that sex differences in attachment reflect the activation of sexually differentiated pathways organized in early development, and for the first time implicate sex hormones in the development of individual differences in attachment styles.

show abstract

The development of sex differences in digital formula from infancy in the Fels Longitudinal Study

Cited by 217 publications

References 27 publications

Digit ratio (2D:4D) in newborns: Influences of prenatal testosterone and maternal environment

Digit ratio (2D:4D) in newborns: Influences of prenatal testosterone and maternal environment

Digit ratios (2D:4D) determined by computer‐assisted analysis are more reliable than those using physical measurements, photocopies, and printed scans

Digit Ratio (2D:4D) and Attachment Styles in Middle Childhood: Indirect Evidence for an Organizational Effect of Sex Hormones

Contact Info

Product

Resources

About