Can Finger Length Predict Penis Length?
The famous myth that a man's hands can reveal how ‘well-endowed’ he is has been put to the test during the last decade. One notable study was published in 2011 by the Asian Journal of Andrology. Scientists measured the relationship between the length of the right hand's index and ring fingers (2D:4D digit ratio) and the length of the penis. They found a significant correlation.
The study, carried out in South Korea, involved 144 men who would undergo urological surgery, and sought to avoid the influence of external factors in the measurements. Firstly, one of the researchers measured the length of the index and annular fingers of the patients twice with a pachymeter and averaged the measurements. Another researcher (who had no knowledge about his colleague's work) was charged with measuring the penises of the volunteers, at rest and stretched. Patients were measured lying down, right after stripping to lessen the effects of temperature variation and touch on the genitalia. This measurement was also taken twice and averaged.
They found was that the 2D:4D ratio in the right hand is correlated to the size of the penis: the shorter the index finger compared to the ring one, the longer the penis. The relationship only applies to the specific situation of a stretched flaccid or erect penis (found to be similar). According to the researchers there is no relationship between the flaccid penis and the 2D:4D ratio. However, they found a positive correlation with the height of the subjects: the taller a man is, the longer his penis is at rest (flaccid). This result corroborates two other surveys done in 2001 and 2007.
Scientists hypothesize that such a correlation is associated with prenatal androgen exposure in the womb, which is thought to regulate the 2D:4D ratio. Numerous studies have found that higher levels of testosterone in the womb result in a smaller ratio and more prominent male traits, such as a deep voice, a masculine face, and even traditionally masculine personality and behavioral traits. On average, the digit ratio is smaller in men and bigger in women. 2D:4D has, therefore, been found to correlate with multiple sexually dimorphic anatomical and behavioral metrics, and even disease epidemiology.
The results are beginning to be used on several research fronts to further investigate human health, anatomy and development. A statistically significant correlation with penis size would be yet another evidence for the link between prenatal androgen regulation of sexually dimorphic traits.
Intriguing yet unclear correlations
The findings are intriguing, but there is still no guarantee they are empirically meaningful. It isn't yet possible to draw an exact formula for the 2D:4D ratio and the size of the penis given that the digit ratio varies between ethnicities to a greater extent than between genders. A much broader study is necessary to reach definitive conclusions. Furthermore, this study is perfectly not in line with a paper from 2002, which proposes a positive correlation between index finger and penile size.