Comparing criminals with their biological and adoptive parents to explain criminal behaviour
If the child is more similar to their biological parents than adoptive parents
A genetic basis of criminality may be suggested
If the child is more similar to their adoptive parents than biological parents
An environmental argument for criminality is preferred
Adoption studies
Hutchings and Mednick (1975) studied 14,000 adopted children and found a high proportion of boys with criminal convictions had biological parents with criminal convictions too, suggesting a link between aggression and genetics
Mednick et al. (1994) found no relationship between the number of criminal convictions of adoptive parents and their adopted children but did find a significant correlation between the number of criminal convictions of the biological parents and their offspring
