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

Abstract

The 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. © 2016 Wiley Periodicals, Inc.

Association of primary dysmenorrhea with anthropometrical and socio‐economic factors in Polish university students

“…those who had been exposed to higher testosterone level and lower estrogen levels in the prenatal period, were most likely to suffer from painful menstruation. To the best of our knowledge, in research literature there are no works on the relationship between the digit ratio and menstrual disorders; however, the result presented in scientific literature suggest that 2D:4D digit ratio might have a life‐long connection to women's reproduction, with an impact on both duration of reproductive lifespan and, the reproductive success . It is also worth mentioning that the digit ratio is held to be strongly correlated with the hormone levels during the fetal period, although it bears no relation to sex hormone levels in adult life …”

“…To the best of our knowledge, in research literature there are no works on the relationship between the digit ratio and menstrual disorders; however, the result presented in scientific literature suggest that 2D:4D digit ratio might have a life-long connection to women's reproduction, with an impact on both duration of reproductive lifespan and, the reproductive success. 42 It is also worth mentioning that the digit ratio is held to be strongly correlated with the hormone levels during the fetal period, although it bears no relation to sex hormone levels in adult life. [43][44][45][46] We may expect that the effect of sex hormones in the prenatal period, as manifested by the digit ratio, on the prevalence of dysmenorrhea is indirect.…”

Low digit ratio (2D:4D) is associated with early natural menopause

“…Nevertheless, the effects of intrauterine hormone exposure, estimated by 2D:4D, on female life history traits and fertility patterns were tested in some previous studies. Klimek et al () reported a higher reproductive success among women with a more feminine digit ratio. In detail, these women had a higher number of offspring, gave birth to their last child at a later age and exhibited a longer reproductive life span.…”

“…Digit ratio was calculated by dividing the length of the index finger to the ring finger, that is, 2D: 4D. Based on digit ratio value, participants were divided into two groups: low or masculine 2D:4D <1 or high or feminine 2D:4D ≥1, following previously published studies (Klimek et al, , ).…”

“…The underlying mechanism for the correlation between 2D:4D and prenatal sex hormone levels may be the action of the Homeobox genes, which control the differentiation of digits but also of the gonads, that is, testes and ovaries (Manning, ). The 2D:4D ratio as a proxy of intrauterine sex hormone levels, correlates significantly with various somatic features, fertility parameters, behavioral traits (Fink, Manning, & Neave, ; Klimek, Galbarczyk, Nenko, Alvarado, & Jasienska, ; Klimek, Galbarczyk, Nenko, & Jasienska, ; Lyons, ; Manning, Scutt, Wilson, & Lewis‐Jones, ) but also pathologies such as breast cancer risk (Muller et al, ). The aim of the present study was the analysis of association patterns between 2D:4D ratio and age at menopause.…”