“Biological theories of crime focus on the physiological, biochemical, neurological, and genetic factors that influence criminal behavior. However, such theories also stress the complex link between a person's biology and the broad span of social or environmental factors that sociological theories examine” (Denno, 2009).
Biological factors that contribute to crime are something neurological or chemical related, which is not to be confused with a genetic factor that is inherited from one parent. For example if a person has a predisposed gene that they got from the father side of the family. The father and grandfather were serial murderers and therefore the child is. Biological factors are different in that they are more internal. A good example is a person that has been in a bad car accident where they were thrown through the windshield and as a result suffered massive head trauma. His or her ability to reason thoroughly has been skewered and the portion of the brain that controls reason and morality are now affected or damaged. This person now commits criminal acts, acts violently towards others and has been detained by authorities on three separate occasions.
The injury is a contributor for this person’s action if previous review or research showed they had symptoms prior. We must also consider the biochemical aspects that affect crime, such as chemical imbalances and high levels of stress. “Stress often results in chemical imbalances in the brain. When the brain becomes overactive and emotions such as fear, anger, guilt, or insecurity occur constantly a state of stress occurs in the body. The "nature vs. nurture" debate still continues in the field of criminology. However, the evidence is mounting that both factors are important ingredients in forming criminal personality. The principal cause of violent crime appears to be a biochemical predisposition triggered by environmental stress” (Walsh, 1988). Sociological Theories