NEW YORK (Reuters Health) - How long a man's second finger is relative to his fourth finger appears to predict whether he is prone to be physically aggressive toward others, according to a new study by researchers at the University of Alberta, Edmonton, Canada. But it's not finger length that causes aggression, study author Allison A. Bailey warned in an interview. She explained that the important factor is the male hormone testosterone. Fetuses are exposed to various levels of this hormone in the womb, and research shows that men who were exposed to higher levels tend to have shorter second...