Sexual orientation and the second to fourth finger length ratio: A meta-analysis in men and women.

Abstract

The ratio of the lengths of the second and fourth fingers (2D:4D) may serve as a marker for prenatal androgen signaling. Because people are typically unaware of their 2D:4D, its use allows possible effects of early sex hormone regimes and socialization to be disentangled. We conducted a meta-analysis on relationships between 2D:4D and sexual orientation in men and women in 18 independent samples of men and 16 independent samples of women. Collectively, these samples comprised 1,618 heterosexual men, 1,693 heterosexual women, 1,503 gay men, and 1,014 lesbians. In addition to identifying the normative heterosexual sex difference in 2D:4D for both hands, we found that heterosexual women had higher (more feminine) left- and right-hand 2D:4D than did lesbians, but we found no difference between heterosexual and gay men. Moderator analyses suggested that ethnicity explained some between-studies variation in men. These results add to a literature suggesting that early sex hormone signaling affects sexual orientation in women, and highlight the need for further research exploring the relationships among 2D:4D, sexual orientation, and ethnicity in men.

Click-Evoked Otoacoustic Emissions in Children and Adolescents with Gender Identity Disorder

“…Another supposed retrospective indicator of relative androgen exposure during early development is the ratio between the length of the index finger and the ring finger, the 2D:4D ratio (Grimbos, Dawood, Burriss, Zucker, & Puts, 2010;Hönekopp & Watson, 2010;McFadden & Shubel, 2002;Peters et al, 2002;Williams et al, 2000). Although OAEs and digit ratios, when directly compared, showed no correlation (McFadden & Shubel, 2003;Snihur & Hampson, 2011), these two measures may provide complementary evidence for early androgenic effects on neurobiological sexual differentiation.…”

Para além de um corpo transparente: investigando métodos e estratégias de esquadrinhar o sujeito homossexual

“…Para estudar a relação entre o segundo e quarto dígitos (2D:4D), as seguintes técnicas foram empregadas: fotocópias eletrostáticas das mãos; medidas realizadas diretamente nas mãos dos/ as participantes; digitalizações ou marca de tinta das mãos (Rahman, Wilson, Abrahams, 2004;Robinson, Manning, 2000;Rahman, 2005b;Rahman, Wilson, 2003a;Grimbos et al, 2010).…”

“…Alguns estudos analisados utilizaram dados disponíveis nos arquivos do Kinsey Institute for Sex Research, ou, para "classificar" os sujeitos quanto à "orientação sexual", empregaram a escala Kinsey, modificada ou não (Rahman, Wilson, Abrahams, 2004;Bogaert, 1997;Bogaert, Blanchard, Crosthwait, 2007;Hershberger, Bogaert, 2005;Rahman, 2005b;Rahman, Wilson, 2003a;Grimbos et al, 2010).…”

Sex differences in anogenital distances and digit ratios in wild David’s rock squirrels Sciurotamias davidianus

“…Numerous studies on 2D:4D in humans provide clear evidence for sexual dimorphism (Manning et al, 1998;Manning, 2002;Saino et al, 2006;Grimbos et al 2010;Nelson et al, 2011;Zhao et al, 2012). Non-human studies conducted so far have, however, yielded inconsistent results, although sexual dimorphism in 2D:4D has been found in some of the tested species, including amphibians (Oophaga pumilio: Chang, 2008) Romano et al, 2005;Saino et al, 2007), and mammals (rodents: Brown et al, 2002;Manning et al, 2003;Leoni et al, 2005;Yan et al, 2008;primates: Roney et al, 2004;McIntyre et al, 2009;Nelson and Shultz, 2010).…”

“…In the human literature, some sexually differentiated traits reliably relate to 2D:4D (e.g. sexual orientation: Grimbos et al, 2010), while others do not (e.g. aggression and spatial cognition: Honekopp and Watson, 2011;Puts et al, 2008).…”