Second to fourth digit ratio a predictor of penile length

January 01, 0001

Second to fourth digit ratio a predictor of penile length

The second to fourth digit ratio (2D:4D) has been proposed as a putative biomarker for prenatal testosterone and covaries with the sensitivity of the androgen receptor (AR). Both prenatal testosterone and the AR play a central role in penile growth. In this study, the researchers investigated the relationship between digit ratio and penile length. Korean men who were hospitalized for urological surgery at a single tertiary academic centre were examined in this study, and 144 men aged 20 years or older who gave informed consent were prospectively enrolled. Right- hand second- and fourth-digit lengths were measured by a single investigator prior to measurement of penile length. Under anaesthesia, flaccid and stretched penile lengths were measured by another investigator who did not measure nor have any the information regarding the digit lengths.

Univariate and multivariate analysis using linear regression models showed that only height was a significant predictive factor for flaccid penile length and that only digit ratio was a significant predictive factor for stretched penile length.

The researchers concluded: "…. the digit ratio can predict adult penile size and that the effects of prenatal testosterone may in part explain the differences in adult penile length."

This has also been linked to risk of prostate cancer (http://www.globalfamilydoctor.com/search/GFDSearch.asp?itemNum=12163). There is evidence elsewhere that this is externally generalizable beyond the Korean population.

For the full abstract, click here.

Asian Journal of Andrology published online 4 July 2011 © 2011 SIMM, CAS and SJTU
Second to fourth digit ratio: a predictor of adult penile length. In Ho Choi, Khae Hawn Kim, Han Jung et al. Correspondence to Tae Beom Kim: [email protected]

Category: Y. Male Genital System, Breast. Keywords: digit ratio, flaccid penile length, stretched penile length, measurements, cohort study, journal watch.
Synopsis edited by Dr Stephen Wilkinson, Melbourne, Australia. Posted on Global Family Doctor 19 July 2011

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