The ratio of index and ring finger lengths (2D:4D) is thought to be a marker of prenatal androgen exposure. In a sample of over 2,000 participants, men had significantly lower 2D:4D ratios than women (d = .36 and .23 for right and left hands, respectively), and these results were consistent across ethnic groups. Heterosexual men had significantly lower (more male typical) 2D:4D ratios than gay ...

In an experiment using two-bidder first-price sealed bid auctions with symmetric independent private values, we scan also the right hand of each subject. We study how the ratio of the length of the index and ring fingers (2D:4D) of the right hand, a measure of prenatal hormone exposure, is correlated with bidding behavior and total profits. 2D:4D has been reported to predict competitiveness in ...

We tested the association between a biomarker of early sex differentiation, the second-to-fourth finger length ratio (2D:4D), and unprovoked attack during a simulated war game (n = 176). We also investigated whether 2D:4D mediated the tendency for men to attack more than women and whether personality dimensions previously associated with sex differences in aggression or hostility (social domina...

In an experiment using two-bidder first-price sealed bid auctions with symmetric independent private values and 400 subjects, we scan also the right hand of each subject. We study how the ratio of the length of the index and ring fingers (2D:4D) of the right hand, a measure of prenatal hormone exposure, is correlated with bidding behavior and total profits. 2D:4D has been reported to predict co...

The etiology of multiple sclerosis (MS) is complex, involving genetic and environmental risk factors and their interactions. Furthermore, evidence suggests that the timing of exposure to environmental factors may be important. The exploration of risk associated with exposures distant in time, e.g., in childhood, or even before birth, presents particular difficulties. For example, month of birth...

Sexual differentiation leads to the development of distinctive anatomical structures (e.g., gonads and genitalia); it also produces less obvious anatomical shifts in brain, bones, muscles, etc. This study is a retrospective analysis of growth patterns in the hands in relation to sex and sexual orientation. Using data from three published studies, we analyzed four hand traits in adults: hand wid...

The ratio of index finger length to ring finger length (2D:4D) is an index of prenatal androgen exposure. In a study with 71 female and 52 male undergraduate students, we assessed the relationship between 2D:4D and jealousy with respect to various dimensions of rival characteristics. Following the presentation of a jealousy-evoking scenario, participants rated the extent to which they would fee...

Androgen-dependent signaling regulates the growth of the fingers on the human hand during embryogenesis. A higher androgen load results in lower 2D:4D (second digit to fourth digit) ratio values. Prenatal androgen exposure also impacts brain development. 2D:4D values are usually lower in males and are viewed as a proxy of male brain organization. Here, we quantified video gaming behavior in you...

The etiology of androgenic alopecia (AGA) involves several factors, including genetics, androgens, age and nutrition. Digit-length ratio of the index and ring finger (2D:4D) is an indicator of prenatal exposure to sex hormones. There is a paucity of studies that systemically review the possible positive predictive value of 2D:4D in the development of AGA. We performed a single-site, descriptive...

The prenatal hormonal environment plays an important role in organizing sex differences in the morphology, physiology and behavior of humans as well as other vertebrates. Currently, all related research on rodents has been focused on Myomorpha. This study presents data on sex differences in the anogenital distance (AGD) and the ratio of the second to the fourth digit length (2D:4D) from 44 wild...