Brief Communication: Women with more feminine digit ratio (2D:4D) have higher reproductive success

ObjectivesPrenatal development has a long-lasting influence on biological condition and health. Second-to-fourth digit ratio (2D:4D) is suggested as an indicator of sex hormone exposure during fetal development, and it is likely that women with a more feminine digit ratio were exposed to higher prenatal estrogen levels. Therefore, we tested if 2D:4D was related to a woman's reproductive characteristics. MethodsWe studied 319 women aged 46-92, who went through a natural menopause and whose husbands were alive at least until their menopause were studied. Women were recruited at the Mogielica Human Ecology Study Site located in rural Poland. ResultsWomen with more feminine 2D:4D had a higher number of children (P=0.002), gave birth to their last child at a later age (P=0.02), and had a longer reproductive lifespan (P=0.04) than women with more masculine 2D:4D. Age and number of years of education were included as potential confounders in the analyses. ConclusionsThe results indicated that women with more feminine 2D:4D had higher reproductive success. While the exact mechanisms were not known, and the relationship between 2D:4D and adult sex hormone levels was questioned by previous studies, there might be other biological pathways explaining the observed results, that is, via behaviors that were indirectly related to fertility. Am J Phys Anthropol 160:549-553, 2016. (c) 2016 Wiley Periodicals, Inc.