"Researchers have hypothesized that foot fetishism increases as a response to epidemics of sexually transmitted diseases. In one study, an increased interest in feet as sexual objects was observed during the great gonorrhea epidemic of twelfth century Europe and the syphilis epidemics of the 16th and 19th centuries in Europe. In another study, the frequency of foot-fetish depictions in pornographic literature was measured over a 30 year interval. An exponential increase was noted during the period of the current AIDS epidemic. The researchers noted that these epidemics overlapped periods of relative female emancipation. Sexual focus on female feet was hypothesized to be a reflection of a more dominant posture of the woman in sexual-social relations."
"Hair whorls on the head (parietal whorls) have been intensively studied because of the association indicated between brain development and abnormal hair whorls. (Both brain cells and skin cells are derived from an embryo's ectoderm tissue.) Abnormal hair whorls are used as a preliminary predictor of abnormal temperament in most domesticated animals, especially cows, but also in evaluating the mental status of apes and humans. A recent study found that homosexuals are more likely to have the less common counter-clockwise hair whorl phenotype than heterosexuals. Right and left handedness have also been linked to clockwise and counter-clockwise whorls, respectively."