INCHEON, South Korea, July 5 (UPI) -- How much longer a man's ring finger on the right hand as compared to the index finger is an indicator of penis length, researchers in South Korea say.
Study leader Tae Beom Kim of Gachon University in South Korea said, "To date, there have been few studies that reveal why men who undergo normal puberty have different penile lengths," the Sydney Morning Herald reported.
The research team says they measured the penises of 144 men admitted to hospital for urological surgery, using a ''rigid ruler," while the men were under anesthesia.
The researchers also measured the digits of the men's right hands.
In most women, these two fingers are about the same length. But men's index fingers tend to be shorter than their ring fingers, giving a lower digit ratio, the researchers say.
The study, published in the Asian Journal of Andrology, found that height was a good predictor of flaccid penile length, but stretched penile length -- a better indicator of erection length -- was linked to the finger ratio.
A lower ratio -- or a shorter length of the index finger compared to the ring finger -- was linked to a longer penis length.
The study also says in most women, the index and ring fingers are about the same length, but men's index fingers tend to be shorter than their ring fingers resulting in a lower digit ratio, the study says.