title: Digit ratio (2D:4D) and handgrip strength in Hani ethnicity.
abstract: BACKGROUND
  The ratio of the length of the second finger to the fourth finger (2D:4D) in humans is considered as a putative marker of prenatal exposure to testosterone, and has been progressively adopted as one useful tool to evaluate the effect of prenatal hormones in some traits such as physical ability. Handgrip strength is one authentic measure of physical ability and is generally used on the anthropological research within an evolutionary viewpoint.
  
  
  METHODS
  Here we present the first evidence on 2D:4D and handgrip strength on adult participants of Hani ethnicity and explore the relationship between digit ratio (2D:4D) and handgrip strength. We examined 2D:4D and handgrip strength of 80 males and 60 females at Bubeng village, in the Yunnan province of China.
  
  
  RESULTS
  The mean 2D:4D in females was higher than that in males for each hand. Females showed significantly higher 2D:4D than males in the right hand rather than in the left hand. Males displayed significantly higher handgrip strength than females for both hands. Handgrip strength decreased with age for both sexes. A significant negative correlation between 2D:4D and handgrip strength was found in the right hand of males.
  
  
  CONCLUSIONS
  The relationship between 2D:4D and handgrip strength may be attributed to evolutionary drive of sexual selection operating on fetal programming.
authors.affiliation: Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, China ; College of Life Sciences, Northwest University, Xi'an, China.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Zhao
authors.forename: Keli
authors.initials: K
authors.lastname: Yu
authors.forename: Xinghua
authors.initials: X
authors.lastname: Zhang
authors.forename: Lianbin
authors.initials: L
authors.lastname: Zheng
mesh_terms: D000328:Adult; D000368:Aged; D002681:China; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D005385:Fingers / Q000033:anatomy & histology*; D007839:Functional Laterality / Q000502:physiology*; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D055815:Young Adult