2D:4D digit ratio and religiosity in university student and general population samples

The ratio of index to ring finger length (2D:4D) is used as a proxy for prenatal sex hormone exposure. It has been hypothesised to correlate with religiosity, though no published research has explored this possibility. Here, we initially examined 2D:4D in relation to self-reported religious affiliation and questionnaire measures of general religiosity, spirituality, religious fundamentalism, and religious commitment in male (N = 106) and female (N = 105) university students (Study 1). Although no significant correlations were observed between 2D:4D and the questionnaire measures, females who affiliated with organised religions had higher digit ratios compared to agnostic or atheist females. Study 2 attempted to replicate these findings in an adult general population sample (N = 172 males, N = 257 females), but did not observe significant effects in either sex. Overall, these findings suggest that high 2D:4D may be relatively-specifically associated with religious affiliation in young, highly-educated, females.