Prospective investigation of penile length with newborn male circumcision and second to fourth digit ratio

Jong Kwan Park, A. Ram Doo, Joo Heung Kim, Hyung Sub Park, Jung Mo Do, Hwang Choi, Seung Chol Park, Myung Ki Kim, Young Beom Jeong, Hyung Jim Kim, Young Gon Kim, Yu Seob Shin


Introduction: We prospectively investigated the relationship between newborn male circumcision (NMC) and second to fourth digit ratio with penile length.

Methods: As participants for our study, we identified already circumcised young patients who visited our hospital for urological treatment. The age at which the circumcision had been done was assessed. The patients’ height and weight were measured. Second to fourth digit ratio was calculated by measuring the second and fourth digit lengths. The flaccid and erectile penile lengths were measured from the base of the penis to the tip of the glans in standing position.

Results: A total of 248 patients were included in our study. In univariate analysis, height, second to fourth digit ratio, flaccid penile length, and age of circumcision were associated with erectile penile
length. Among these variables, second to fourth digit ratio, flaccid penile length, and age of  circumcision were significant predictive factors for erectile penile length in multivariate analysis. The subjects were divided into two groups, including 72 patients in the NMC group and 176 patients in the non-NMC group. No significant difference was found in height, weight, and second to fourth digit ratio between both groups. However, flaccid (p<0.001) and erectile (p=0.001) penile lengths were shorter in the NMC group than in the non-NMC group.

Conclusions: Despite the small number of subjects, this study shows that NMC was associated with shorter penile length. Second to fourth digit ratio, flaccid penile length, and age of circumcision were also significant predictive factors for erectile penile length. Further multicentre studies with larger number of subjects and biochemical analyses are needed for potential clinical applicability

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