(CBS) - Despite the rumors, shoe size and hand size won't predict a man's size...down there. What can? Researchers at Gachon University in Incheon, South Korea think they've found the answer.
They say two fingers can tell the whole tale.
For the study, published in the Asian Journal of Andrology, researchers looked at the relationship between the size of the second digit, or index finger, and that of the fourth digit, the ring finger - in 144 Korean men aged 20 or older. All these men were in the hospital undergoing urological surgery for conditions unrelated to penis length.
After measuring pre-and post-surgery lengths for all three "digits," the researchers found the average length between the second and fourth finger was 0.38 inches, and ranged from 0.35 to 0.44 inches, according to LiveScience. These measurements may be too small for the naked eye to notice, but when the researchers compared these finger lengths with penis size, they found the lower the digit ratio, the longer the penis was.
What does that mean?
"According to our data...the shorter index finger than ring finger you have, the longer stretched penile length you have," Dr. Tae Beom Kim, study author and professor of urology at Gachon University in Incheon, South Korea, told Reuters.
Put your hands down, fellas. These findings may serve as fraternity fodder, but what are the medical implications of studying digit size?
Several studies have linked the distance between the second and fourth finger to sperm count and heart attack risk, LiveScience reported. But finger size has also been linked to other deadly diseases.
Dr. Denise Brooks McQuade, professor of biology at Skidmore College in N.Y, wrote in an accompanying commentary to the study, that digit ratio can help doctors gauge how much testosterone a fetus is exposed to in the womb, which has been linked to an increased risk for hormone-driven diseases like prostate cancer.
She points to a 2011 study that found participants that had an "index finger longer than ring finger were significantly less likely to have prostate cancer." The authors of that study said a high digit ratio might display a protective benefit these patients have against the disease, according to her commentary.
"Digit ratio is non-invasive and easy to measure, yet may provide clues about an individual's prenatal history." McQuade told Reuters. "Combined with other information, digit ratio offers the potential for clinical usefulness."
Maybe size does matter.