Despite the endless research conducted in this area of ​​study, researchers still have difficulty determining the cause of serial killers. So the main question is: are serial killers born or made? As mentioned above, researchers have identified a number of biological predispositions linked to these groups of people. In fact, since the beginning of time, it has been believed that criminals are born and not made. Dating back to the 19th century, Lombroso examined the phenotypes of Italian criminals to determine whether criminal characteristics could be passed down through generations. He hypothesized that criminals were born callous and cruel while lacking remorse. Lombroso also mentioned that these individuals tended to be antisocial. Although many of these theories have been disproved by modern research, researchers have admitted some underlying truths from outdated studies. Take for example Lombroso's experiment, which managed to distinguish a hereditary link between future violent behavior. Interestingly, genetics accounts for approximately 40-60% of antisocial and aggressive behaviors. According to adoptive studies, there is a 12.1% chance that a child will develop violent tendencies if his or her biological parent is violent. Jeffrey Landrigan is a perfect example of this. Landrigan was given up for adoption when he was born. Growing up he exhibited various delinquent behaviors. At the age of 20 Landrigan killed his first victim. By the age of 25 Landrigan had killed two people and was sentenced to death. While in prison, Landrigan was revealed to be related to another inmate, Darrel Hill, who was his father. Like his father, Landrigan had abused drugs and committed two murders. It was also revealed that Landrigan came from a crime family where his grandfather and great-grandfather were both criminals as well. Landrigan's story and many others like hers are important in developing a greater understanding of crime and serial killers in general by examining correlations between genetics and violent behavior. To refer to the statistics above, genetics can play a significant role in an individual's future, particularly in their likelihood of becoming a delinquent. This is crucial information for several reasons. Not only does it allow for a greater understanding of why an individual may engage in brutal crime, but more importantly, research suggests that regardless of race, gender, or social class, genetics has a universal effect on outcome of humans. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay Despite having a family history of crime, serial killers often suffer from a variety of disorders. Of the 57 adolescents charged with murder, 64 percent had developmental issues with disruptive behaviors, such as conduct disorder, attention deficit hyperactivity disorder (ADHD), and autism spectrum disorder. Recent studies have found that violent offenders were commonly diagnosed with a neuropsychiatric disorder during their childhood and was often said to be associated with their criminality. Those diagnosed with conduct disorder showed decreased prosocial behavior and physiological responses in stressful situations, as well as increased psychopathic tendencies. These individuals were less likely to help and empathize with others, causing them to react poorly to emotionally challenging events. Due to these individuals' lack of awareness of others' emotions, their interpersonal relationships were affectednegatively. As a result, it is common for these individuals to engage in antisocial behaviors that have been linked to adult criminality. Despite the small population, similar results were found for offenders diagnosed with ASD. It was said that these individuals had difficulty understanding and processing nonverbal communications. It is for this reason that offenders are unable to develop strong relationships with their peers, which makes them socially isolated and unable to fully understand the effects of their actions on others. Therefore, it is not abnormal for these individuals to be involved in more brutal crimes. According to Loana (2013), individuals with Klinefeleter syndrome (KS) are five times more likely to become a serial killer than the general public. KS is a chromosomal mutation that causes an extra sex chromosome (X) to be located in men. A similar disease has been discovered, in which an additional Y chromosome appears in the biological composition of the individual. This has been considered the “crime chromosome,” as the frequency among criminals is 10 times higher than in the general population. A national study confirms this ideology after investigating the criminal patterns of males ages 15 to 70 diagnosed with KS and XYY. It turned out that men with an extra sex chromosome were more likely to be convicted than the general public. A significant increase was found among offenders of sexual abuse, burglary, arson and 'other' convictions. These high conviction rates are believed to be due to low IQ levels and poor socioeconomic status. It is common for men diagnosed with these diseases to experience additional psychiatric disorders, psychophysiological dysfunction, and/or increased sexual deviance. It is believed that these sexual deviations are due to confusion related to the sexuality of these individuals and the inability to distinguish socially and legally accepted behaviors; explaining the high levels of sexual abuse convictions among these people. Brain Regions and Chemical Imbalances The brain is a complex, organized structure that controls how humans think and behave. It is separated into two parts: the left and right hemispheres; bilateral operation. A crossover of information occurs and is dominated by the left or right hemisphere. The result is that the left side of the body is controlled by the right hemisphere and vice versa. It is important to note that the brain is location dependent; this means that each region has its specific functions. Therefore, damage to a region can result in specific behavioral outcomes. These outcomes are typically referred to as dysfunctions, since the individual is unable to produce the same behaviors as a typically healthy person in the same environment and situations. In recent studies, a strong positive correlation has been discovered between serial killers and head trauma, where an increase in violent behavior is believed to occur after the trauma. This can occur during childbirth or due to an unfortunate event, such as a fall or a blow to the head. Take Robert Long, for example, after he was in a motorcycle accident and suffered a head injury. There has been an increase in violent behavior, leading to the commission of violent crimes. Long was said to have suffered damage to his left temporal lobe. Located in the temporal lobe is the limbic system, which is notoriously known for its involvement in human emotions. Dysfunctions of the limbic system, particularly the hypothalamus, can cause hormonal and neurotransmitter imbalances resulting in a lack of prosocial behaviors and.