The biological explanation of crime is a structural one and argues that some people have a predisposition to engage in criminal activity, due to inherited genes. In the past it was claimed that criminal behaviour could be attributed to brain size and a certain shape of skull. This theory has long been discredited, however it gave rise to the more disquieting practice of eugenics. Most notable was the breeding programme under the Nazi regime, in the early twentieth century. The more recent biological explanations of crime by modern geneticists are supported by a much deeper understanding of DNA legacy. The basic theory is that the DNA of two parents are combined to make up the new DNA of their offspring, therefore traits and characteristics of the parents will invariably be passed onto the child.
There has been extensive research in this field, most notably in the study of twins and adopted children.
Research by K.O. Christiansen, has shown that identical twins are far more likely to share the same personality traits and criminal inclinations than non identical twins and siblings, reinforcing the theory that criminal tendencies are in ones genetic make up (identical twins originate from the same egg and therefore share the same DNA. Non identical twins have differing DNA because they come from separate eggs). There are however, social factors which may have a bearing on the results of the research, i.e. it has been widely noted that identical twins are generally treated as one and usually have a very similar upbringing, therefore they are likely to encounter the same social influences and messages.
Sarnoff Mednick's research has focused on adopted children, as it better isolates genetic links from social factors. His research has shown that personality and behaviour patterns of adopted children are more similar to...