The theory of criminal genetics states that criminals don’t have a choice when they commit crimes and were already genetically predisposed to commit these acts. Although the justice system doesn’t always accept the theory there is some merit to it take a look at the case of Jeffrey Landrigan, he was born Billy Hill his father raped his mother and later married her. While with child his mother abused alcohol and drugs, after his birth Billy’s father went to prison and his mother gave him up for adoption. After his adoption and renaming by the Landrigan family Jeffery had a troubled childhood with frequent run-ins with law enforcement and in 1982 at the age of 20 he was sent to a minimum security prison for killing his best friend where he later escaped to Arizona and killed again. After the Arizona killing Landrigan was sentenced to death row, later on when his appeal was rejected Landrigan’s lawyers sought habeas corpus on the grounds that that Landrigan deserved to introduce evidence of mitigating factors meaning his genetic predisposition to disordered behavior, the claim is that due to his mother’s drug and alcohol abuse while pregnant with him, being given up for adoption, his adoptive mother’s alcohol abuse, and his own drug and alcohol addiction caused him to commit the murders. The courts denied habeas corpus emphasizing that the genetic evidence has “shown the court that it could anticipate his continuance of violence.” Landrigan’s case can be looked at as an adoption study, this type of study is done to determine how similar an adopted person is to their biological family and to see how their new environment affects them.

Another type of study is the twin study, this is a study is done to see if two individual that share the same genetic material and the same environment have the same disposition to criminal behavior. These studies show that