Is the Index Finger and Ring Finger Ratio (2D:4D) Reliable Predictor of Semen Quality?

PURPOSE: The purpose of this paper is to test the validity of hypothesis that the index finger and ring finger ratio (2D:4D) is related with men's semen quality. MATERIALS AND METHODS: We set two groups of healthy young male student (mean age 23.9) who have different 2D:4D ratio from different departments of Chosun University. One group consists of 26 men whose 2D:4D ratio is higher than 1 (mean 1.06), and the other group consists of 33 men whose 2D:4D ratio is lower than 1 (mean 0.94). Their semen was collected by masturbation and examined. RESULTS: A comparative analysis revealed that there is no relation between semen quality and the 2D:4D ratio. The group of 2D:4D≥1 showed a semen volume of 3.66±1.64 ml, on the other hand, the group of 2D:4D<1 showed a semen volume of 3.73±1.40 ml. No statistical correlation was found (p=0.82). The view of sperm count and motile sperm in single ejaculated semen also showed no statistically significance with 2D:4D ratio (p=0.84, p=0.43, respectively). CONCLUSIONS: The 2D:4D ratio has no statistically significant correlation with the semen quality of health young male. Thus, measurements of finger length cannot be a reliable indicator of semen quality and testicular function.