All those jokes about the size of men's feet... or hands...
Well, new research demonstrates that there might actually be something to the idea that there is a correlation between length... and length.
A team of South Korean researchers studied 144 men, and came up with what may be a reliable guide: the ratio of the length of a man's index finger to that of his ring finger. The lower that ratio, the longer the penis may be, the researchers wrote Monday in the Asian Journal of Andrology, according to the Los Angeles Times.
The team, led by Tae Beom Kim of Gachon University in Incheon, said it investigated this apparent correlation because it believed there was a lack of research on the male appendage, according to the Sydney Morning Herald. ''To date, there have been few studies that reveal why men who undergo normal puberty have different penile lengths,'' it said.
The researchers studied the men's right hands. Digit ratio, or the length of the second, index finger relative to the fourth, ring finger, was calculated. In most women, those 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 length of the penis was measured both when it was flaccid and when it had been stretched to its full length, according to the Los Angeles Times. Stretched length is thought to correlate to erect length, the researchers said. They found that, in general, the lower the ratio of the lengths of the two fingers, the longer the penis was in its stretched state.
The key to this relationship may lie in the womb, the team said. Previous research has indicated that prenatal testosterone may determine finger development as well as penile length, a relationship that inspired Kim and his colleagues to design a study to focus on it, according to Reuters, which added:
The findings offered "circumstantial evidence that prenatal testosterone is responsible for both traits (penile length and digit formation,)" said Denise McQuade at Skidmore College in New York, who was not involved in the study.
Other recent findings have suggested that men with a lower ratio have a more symmetrical face and are more attractive to women, a phenomenon that has been referred to as the "sexy ratio," according to the Los Angeles Times. And last year, researchers at Warwick University and the Institute of Cancer Research in Britain reported that a man's risk of developing prostate cancer is also related to the ratio of the two fingers. Men whose index fingers were longer than their ring fingers were found to be one-third less likely to develop prostate cancer.