From the storied Halls of Science comes an important new study, here abstracted from the Asian Journal of Andrology1. I apologize for the length of this excerpt, but it is necessary you read it all (viaPubMed; spaces entered for readability):
The second to fourth digit ratio (2D:4D) has been proposed as a putative biomarker for prenatal testosterone and covaries with the sensitivity of the androgen receptor (AR). Both prenatal testosterone and the AR play a central role in penile growth. In this study, we investigated the relationship between digit ratio and penile length.
Korean men who were hospitalized for urological surgery at a single tertiary academic centre were examined in this study, and 144 men aged 20 years or older who gave informed consent were prospectively enrolled. Right-hand second- and fourth-digit lengths were measured by a single investigator prior to measurement of penile length. Under anaesthesia, flaccid and stretched penile lengths were measured by another investigator who did not measure nor have any the information regarding the digit lengths.
Univariate and multivariate analysis using linear regression models showed that only height was a significant predictive factor for flaccid penile length (univariate analysis: r=0.185, P=0.026; multivariate analysis: r=0.172, P=0.038) and that only digit ratio was a significant predictive factor for stretched penile length (univariate analysis:r=-0.216, P=0.009; multivariate analysis: r=-0.201, P=0.024; stretched penile length=-9.201 x digit ratio + 20.577).
Based on this evidence, we suggest that the digit ratio can predict adult penile size and that the effects of prenatal testosterone may in part explain the differences in adult penile length.
I can shoot a deer without flinching and can gut a fish faster than you can blink. I have even unconcernedly eaten raw frog gall bladders (bitter) and bags of marinated duck tongue. I can walk through an emergency room with complete indifference and am not repulsed by changing diapers of colicky babies.
But I am otherwise squeamish and don’t have the courage to investigate how these researchers got to the “stretched” in “stretched penile length.” I’ll can only assume the method, performed “under anaesthesia”, was charitable and caused no lasting damage.
As far as “flaccid” goes, we have no information on the temperature of the operating room, but let’s hope it remained constant over the duration of the experiment.
In any case, these researchers have given us a new method to predict the length of a man’s certainty without requiring him to drop his shorts. The equation, helpfully given to the third decimal place, and expressed in centimeters, is:
stretched penile length=-9.201 x digit ratio + 20.577.
For those unwilling or unable to do the math, I have prepared this helpful chart. You must first measure the length of your right hand’s forefinger and then divide into this the length of your ring finger. That is the “Second to Fourth Digit Ratio.” Find that ratio and head straight up until you intersect the sloping line. Once there, find the number parallel to it on the left, or y-axis.
I have done this for a ratio of 1 (or 1 to 1). The model predicts that men whose fore- and ring-fingers are the same length have a stretched penile length of 4.5 inches. That is stretched, mind: and recall we have no clear idea what stretched means.
But let’s notice something curious about this graph. I was in the military and, as a consequence, have seen a host of men in, um, various positions of authority (I was Air Force; Navy men will have more knowledge than I). By this, I mean I can report to you that many men are to be found on the upper regions of the y-axis.
According to this model, then, a man of about 7 inches, a far from unheard of territory, is predicted by a digit ratio of 0.2. So if such men have forefingers of 3.25 inches (my measurement), their ring fingers must be 16.25 inches (because 3.25/16.26 = 0.2). My dears, this is one foot, four-and-a-quarter inches. Coney Island itself has never been witness to such freakishness!
What this means is that either this model is a dismal statistical failure, or that Korean men differ substantially from American men, in the direction of being severely shortchanged by Nature or because they are being adversely affected by a steady diet of kimchi. Though I have been to Korea twice, I had no opportunity to take field notes on this consequential topic, so I cannot say which theory is true.
Left unanswered is the most important question of this study: why? I’ll leave that for you to guess.
1Besides the Asian Journal of Andrology, there is the just plain Journal of Andrology, the (exclusive of Asians?) International Journal of Andrology, the (non Asian?) Chinese Journal of Andrology.