This section is from the book "Human Sexuality", by J. Richardson Parke. Also available from Amazon: Human Sexuality.
From a forensic standpoint, therefore, sadism is only interesting as furnishing a key to certain overt acts which—as with those of the man, Brady—might otherwise prove extremely puzzling to the jurist. The fact that an individual feels an almost irresistible impulse to inflict pain upon one of the opposite sex, that impulse being at the same time associated with sexual thoughts and feelings, furnishes no plea for legal clemency, or pity, since every species of crime is more or leas the product of just such impulses; unpremeditated homicide, itself, being but the outgrowth of the psychomotor exaltation of anger, as sadism is of the psychomotor exaltation of lust.
 
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sexuality, reporduction, genitals, love, female, humans, passion