title: Digit ratio (2D:4D) and hand preference for writing in the BBC Internet Study.
abstract: The ratio of the length of the second to the fourth digit (2D:4D) may be negatively correlated with prenatal testosterone. Hand preference has been linked with prenatal testosterone and 2D:4D. Here we show that 2D:4D is associated with hand preference for writing in a large internet sample (n>170,000) in which participants self-reported their finger lengths. We replicated a significant association between right 2D:4D and writing hand preference (low right 2D:4D associated with left hand preference) as well as a significant correlation between writing hand preference and the difference between left and right 2D:4D or Dr-l (low Dr-l associated with left hand preference). A new significant correlation between left 2D:4D and writing hand preference was also shown (high left 2D:4D associated with left hand preference). There was a clear interaction between writing hand preference and 2D:4D: The left 2D:4D was significantly larger than the right 2D:4D in male and female left-handed writers, and the right hand 2D:4D was significantly larger than the left hand 2D:4D in male and female right-handed writers.
authors.affiliation: University of Wales, Swansea, UK.
authors.forename: J T
authors.initials: JT
authors.lastname: Manning
authors.forename: M
authors.initials: M
authors.lastname: Peters
mesh_terms: D000293:Adolescent; D000328:Adult; D001837:Body Weights and Measures / Q000706:statistics & numerical data; D005260:Female; D005385:Fingers / Q000033:anatomy & histology*; D007839:Functional Laterality; D006801:Humans; D020407:Internet; D008297:Male; D012727:Sex Characteristics; D006113:United Kingdom; D014956:Writing