welcome to this CH to you criminology video for wjc level three criminology in this video we're going to look at biological theories of criminality focusing on Twin and adoption studies for assessment criteria 2.1 looking at biological explanations of criminality students need to be aware of the different categories of biological theories such as genetic physiological and biochemistry and brain abnormality twin and adoption studies fall into the genetic category as they focus on the correlations between criminality in Twins and between those that have been adopted and their biological parents genetic explanations look at how criminal behaviors are caused by an individual's genetic structure and this is passed on from biological parent to child whilst with twins genetic structures are either identical in the case of identical twins or similar in the case of non-identical twins but why do we study Twins and those that have been adopted with identical twins also referred to as monozygotic twins those that come from the same egg they have 100% of the same genetic structure if both of the identical twins commit crime we can attribute the cause of crime to genetic factors non-identical Twins or dizygotic twins those those that come from separate eggs do not have 100% of the same genetic material and are less likely than identical twins to behave in a similar way as a result of their genetics different behaviors of identical twins and non-identical twins given they usually brought up in the same environment might be attributed to genetic factors with adoption studies children will have some genetic similarities with their biological parents but will largely not have been socialized by those parents when they were adopted this removes social factors such as socialization as being a cause of criminal Behavior the child despite being removed from the influence of said biological parent if they display criminal behaviors this too can be attributed to genetic factors the parent has passed on their genes and this influen is the child's Behavior twin studies are common in the study of crime Lang found higher concordance levels of criminal behavior in identical twins than non-identical twins which illustrates the power of genetics and explaining behavior in their research they found that 10 out of 13 sets of identical twins both had criminal records compared to just two out of 17 sets of non-identical twins a second study to suggest higher rates of criminality was conducted by christansen analyzing twins in Denmark they found that 35% of twins both had criminal records compared to just 133% of non-identical twins Christian study was also larger than that of Lang which could be criticized for having a small sample size supporting research to twin studies by Ishikawa and Rain found that identical monozygotic twins were more likely to have committed crimes compared to nonidentical or diotic twins which provides evidence to support genetic explanations for Crime however twin studies do have limitations it's harder to separate the impacts of Nature and nurture as most twins we raised in the same household which could explain why they're committing crime they may have similar friends groups and experiences which negatively impact on their behavior and cause them to commit crime furthermore non-identical twins may be socialized differently from one another based upon their personalities whereas identical twins may be perceived as being a pair due to their identical nature a second limitation is that concordance rates of criminal Behavior between identical twins are never 100% if genetics were solely responsible for criminal Behavior then identical twins would both commit crimes yet the findings of research does not bear this out adoption Studies have also found significant concordance rates between biological parents and their children both being criminal Kings and mednik found higher rates of concordance between adopted boys who committed crime and biological parents who had committed crime in a separate study mennik also found lower rates of concordance between adopted boys and those that had adopted them their adoptive parents there was a 20% risk of criminality if boys had a biological parent who' committed crime with just 14.7% risk of adopted boys whose adoptive parents had criminal records whilst these figures show lower levels of difference between biological parents and adopted parents than other studies it's still seen as significant due to the sample size like twin studies we need to examine the strengths and limitations of adoption studies the strength of adoption studies is that as children are removed from their biological parents this reduces the social impacts that may influence criminal behavior and thus allows researchers to concentrate on genetic explanations for behavior however it's often the case that children are placed with adoptive parents that are similar to their own parents in similar locations backgrounds ethnicity and socioeconomic status which means it's difficult to remove all social explanations for criminal Behavior furthermore if children are aware of being adopted the psychological impacts of being adopted could cause criminal and deviant behaviors and this even with adoption studies is difficult to disentangle the social from the genetic explanations behind crime e