AO1

• Genetic explanations suggest offenders inherit genes that make them more likely to be involved in crime
• Twin studies - MZ twins are genetically the same, so common behaviour must be due to their genes: Bartol studied pairs of twins, where one was involved in criminal behaviour to see whether the other twin had also been linked to similar behaviour and found 55% concordance rate for MZ and 12% DZ
• Adoption studies - Crewe found adopted children with biological parent with a criminal record were 50% more likely to have a criminal record than those with a parent who had no criminal record
• Family studies - Farrington (1996) found offending is strongly concentrated in families and is demonstrated from one generation to the next
• Diathesis stress model states alongside genetics, there is likely to be an influence from environment on criminal behaviour via social or psychological triggers eg being in a dysfunctional environment