Digit ratio (2D:4D) in Klinefelter's syndrome

  title={Digit ratio (2D:4D) in Klinefelter's syndrome},
  author={John T. Manning and L. P. Kilduff and Robert Trivers},
The ratio of second to fourth digit length (2D:4D) is a correlate of prenatal testosterone. High 2D:4D is associated with low prenatal testosterone, and reduced sensitivity to testosterone. Klinefelter's syndrome (KS; 47 XXY) affects the endocrine system, such that low testosterone levels are found in KS foetuses, new‐borns and adults. To date, there are no published data regarding the pattern of 2D:4D in KS males. Here we consider 2D:4D in KS individuals (n = 51), their relatives (16 fathers… 
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