Genetic Theories. Flashcards
What does the XYY theory suggest?
It suggests that some crime might be attributable to a chromosomal abnormality.
an extra Y chromosome
Why have XYY men been of interest to criminologists?
Because of the suggestion that they are more aggressive and more inclined to be violent than males with a single Y chromosome.
What does Jacob et al suggest about the XYY syndrome and give a case to back it up?
He suggested that men with the XYY syndrome were more aggressive than normal XY men.
The serial killer John Wayne Gacey is said to have XYY syndrome. He sexually assaulted and killed at least 33 men in the USA.
What do twin studies suggest ?
They support the contention that a heritable trait may increase risk for criminal behaviour
Give an example of one of the earliest twin studies
Lange- he found that MZ twins showed a much higher degree of concordance than DZ twins for criminal behaviour.
What do adoption studies suggest?
The comparison of criminals with both their biological and adoptive parents.
It looks at the impact of nutrients on children who are raised by their non-biological parents.
What do Hutchings and mednick suggest?
They studied 14,00” adopted children and found that a high proportion of boys with criminal convictions had biological parents with criminal convictions too, suggesting a link between aggression and genetics.
However, mednick et al found no relationship between the number of criminal convictions of adoptive parents and their adopted children
