Many mental illnesses are genetically linked and mental illness is already, rightly so, a consideration in our justice system. As with mental illness, a genetic predisposition wouldn't excuse your actions but they certainly could be considered as mitigating circumstances in some cases. The role of the courts isn't to punish or to advocate for the victim, it's to judge the evidence and circumstances impartially. Take the classic example of the man who steals a loaf of bread to feed his starving family, he is clearly wrong to steal but given those circumstances we would all do the same. In a case like this the court would take these mitigating circumstances into consideration when sentencing the man and rather then sending him to jail for stealing he might instead be sentenced to pay back the store for the stolen bread and be given no time in jail. Similarly, the defense lawyer for a person with a genetic predisposition to violence should have a responsibility to argue for a lenient sentence that maybe included anger management training or maybe medical treatment that might allow the individual to better control their anger. The prosecuting attorney would also argue any circumstances against leniency such as prior offenses. Ultimately the court then has to judge based on all the arguments what the best course of action is and that often includes leniency in consideration of the circumstances. I'd much rather a compassionate court system than a punitive one.