The size of a man's fingers is a fair guide to other more discreet measurements, a study has suggested.
Korean scientists studied 144 men and discovered the difference between the length of their second and fourth fingers - digit ratio - was directly linked to penile length.
If the second
and fourth fingers were of similiar length, the longer the penis.
While previous studies have indicated links between digit ratio and prostate cancer, none have revealed why men who undergo normal puberty have different penis sizes.
The men who took part in the study were aged over 20 and had been admitted to hospital for urological surgery.
After having their height, weight and fingers measured, the size of their flaccid and fully stretched penises were recorded while the men were under anaesthetic.
The scientists discovered that while each man's height, ring finger length and digit ratio were all associated with the size of his penis, the digit ratio was the sole "significant predictive factor" for stretched penile length.
Reporting their findings in the Asian Journal of Andrology, the scientists said the individual lengths of fingers had nothing to with penis size.
"However the results ... did show that stretched penile length correlated with digit ratio, as men with a lower digit ratio tended to have a longer penile length," they wrote.
Researchers investigating behavioural and physiological conditions have in the past examined links between digit ratio and hormones.
The Korean scientists said digit ratio was thought to be fixed early in development, in a similar way to how penile growth is influenced by a baby's exposure to testosterone while in the womb.
- AAP
