Here's what they found. The ratio of the length of his index finger to that of his ring finger is the key. The lower that ratio, the longer the penis may be, the researchers wrote Monday in the Asian Journal of Andrology.
Dr. Tae Beom Kim, a urologist at Gachon University in Korea and his colleagues studied 144 men undergoing urological surgery.
One member of the team carefully measured the lengths of the index and ring fingers on the subject's right hand before surgery. The length was measured both when the penis was flaccid and when it had been stretched as much as possible.
Although it may seem like the results are coming out of left field, they actually are not. A variety of studies suggest that the ratio of the two finger lengths is determined by prenatal exposure to sex hormones, both testosterone and estrogen. It is not unreasonable to assume that penis length might also be.