they looked for signs of trouble, signs of criminal bevior, and then classified the children according to wther their biological or genetic background had problem and/or whether or not their adoptive home environment had problems. whatas interesting was that, it took both a bad genetic background and a so-called "bad environment" to produce the highest levels of problems. aggression probably caused many-- caused by many factors like social or environmental situations but biology may also play a role there. there is a dutch family-- they have eight or nine males-- committed a very severe criminal act. when they looked closely, they found there was one particular gene that was abnormal in the violent members of the family. when you have findings in a human, we're not sure whether this is because the missing of this gene or some environment in that family that caused the male give aggressive behavior. so we decided to study in mice, where we can specifically remove one gene and see if it would result into the same aggressive behavior and we find this is the case. you shouldn't think that