Digit ratio
Sounds nutty, but what the heck! Don't blame me if I lose my temper or become violent -- my digit ratio made me do it! ;-)
Finger Length Predicts Health and Behavior (Discover): ... In boys, “during fetal development there’s a surge in testosterone in the middle of the second trimester” that seems to influence future health and behavior, says Pete Hurd, a neuroscientist at the University of Alberta. One easy-to-spot result of this flood of testosterone: a ring finger that’s significantly longer than the index finger.
Scientists are not at the point where they can factor in finger length to arrive at a diagnosis, but they’ve gathered evidence that shows how this prenatal hormone imbalance can affect a person for life, from increasing or decreasing your risk of certain diseases, to predicting how easily you get lost or lose your temper. ...
Increased verbal aggression Fq < 1
Improved athletic ability Fq < 1
Improved sense of direction Fq < 1
More physical aggression Fq < 1
More risk taking Fq < 1