Sexual dimorphism in second-to-fourth digit ratio and its relation to gender-role orientation in males and females

It has been proposed that high prenatal androgens, low prenatal estrogens, or both may be associated with a low (i.e., masculine) second to fourth digit (2D:4D) ratio. The aim of the present study was to examine the association between 2D:4D ratio and gender-role orientation. Participants were 423 male and 312 female university students ranging in age from 18 to 36 years. After filling in the Bern Sex-Role Inventory (BSRI), participants' 2D:4D ratios were measured on both hands. While regression analyses failed to indicate a functional relationship between aspects of gender-role orientation and 2D:4D ratio in the female sample, the BSRI-Femininity score was positively related to the left-hand 2D:4D ratio in males. This finding suggests that a more feminine gender-role orientation in men is associated with lower androgen and/or higher estrogen levels in utero. However, our findings also draw attention to difficulties and inconsistencies in the interpretation of 2D:4D data. (c) 2006 Elsevier Ltd. All rights reserved.