No scientist believes that there is just one "criminal gene" that makes somebody commit a crime. Scientists DO believe that someone's genetic makeup might push them towards doing violent things. One way it can do this is that genes can help control the production of behavior-regulating chemicals. One such chemical is the neurotransmitter serotonin. Neurotransmitters are chemicals that allow brain cells to communicate. The Bowman Gray School of Medicine in North Carolina experimented with this on monkeys. The experiments showed that monkeys with low levels of serotonin were much more violent then monkeys with high levels of serotonin.  This seems to be the same case in human behavior. Some studies have shown that men who commit impulse crimes, like murdering a total stranger, have low amounts of serotonin. Premeditated murders show that the male killers had normal levels. Some scientists believe that females have lower levels of serotonin just before their menstrual period. Scientists say that if there was a drug to increase serotonin it might decrease violent behavior. 

    If a parent could find out that their child would grow up to be a murderer how would they react? They probably wouldn't tell the parents unless they knew that they could do something about it. Dr. Peter Breggin, director of the center for the Study of Psychiatry in Bethesda, Maryland, made a good point. "The primary problems that afflict human beings are not due to their bodies or brains, they are due to the environment," he said. "Redefining social problems as public health problems is exactly what was done in Nazi Germany." I agree with this statement. Genes may make a person feel like doing violent things, but it has to be the surroundings along with the genetics that would make someone take another life.