title: Is low digit ratio linked with late menarche? Evidence from the BBC internet study.
abstract: OBJECTIVE
  Age at menarche (AAM) in the general population may be influenced by prenatal sex steroids. The ratio of the second and fourth digits (2D:4D) is a putative correlate of prenatal sex steroids, but the relationship of 2D:4D to AAM is controversial. Matchock ([2008]: Am J Hum Biol 20:487-489) has reported that right 2D:4D (but not left) was negatively related to AAM, but Helle ([2010a]: Am J Hum Biol 22:418-420) found no relationship. Here the association between 2D:4D, AAM, and self-reported rate of pubertal development (RPD) is considered.
  
  
  METHODS
  The sample consisted of self-measured finger lengths and AAM and RPD reported by women in the BBC internet study.
  
  
  RESULTS
  There were 70,658 white women who reported a mean (± SD) AAM of 12.54 (1.48) years. Right 2D:4D was negatively related to AAM and positively related to RPD. These relationships were independent of left 2D:4D, age and height. Between-country variation in right 2D:4D was also significantly related to AAM such that in countries with low 2D:4D women mean AAM was higher.
  
  
  CONCLUSIONS
  In support of the findings of Matchock, right 2D:4D was found to be negatively related to AAM. In addition, right 2D:4D was positively related to RPD. In a sample of 19 countries, mean right 2D:4D was negatively correlated with mean national AAM. These findings suggest that women with high prenatal testosterone and low prenatal estrogen tend to show late menarche and slow pubertal development.
authors.affiliation: Department of Psychology, University of Swansea, United Kingdom. j.manning@swansea.ac.uk
authors.forename: John T
authors.initials: JT
authors.lastname: Manning
authors.forename: Bernhard
authors.initials: B
authors.lastname: Fink
mesh_terms: D000367:Age Factors; D002648:Child; D005260:Female; D005385:Fingers / Q000033:anatomy & histology*; D006304:Health Status; D006801:Humans; D020407:Internet; D008572:Menarche; D015999:Multivariate Analysis; D011247:Pregnancy; D012016:Reference Values; D012647:Self-Assessment; D013223:Statistics as Topic; D013997:Time Factors; D016387:Women's Health