A team of researchers from the University of Washington carried out a study in order to show that bad and addictive habits, such as smoking, alcohol drinking or using marijuana, may run in the family and transmit from parent to offspring. The University of Washington team sustain that children who have at least one parent to consume tobacco, marijuana, cannabis or alcohol are more likely to develop the bad habit than children whose parents are not practicing such bad, unhealthy habits.

However, the most at risk are offsprings of smokers. "If your parents were smokers, it is a double whammy because you are more likely to use drugs in general and even more likely to smoke cigarettes. There is something about tobacco that if parents smoke, their kids are more likely to smoke. It may be that parents who smoke might leave cigarettes around where their children can see and get to them. Parents may not leave marijuana and alcohol around in the same way," pointed out study co-author Karl Hill, a Research Associate Professor at the University's Social Development Research Group.

The study published in the Journal of Abnormal Child Psychology also insisted on the fact that children of parents with addictive bad habits may develop the unhealthy habit both at an early age and during his/her teen or early adulthood years. Besides the fact that offsprings of smoking or drinking parents may become addicted to the same habit, authors of the study also note that children may develop behavior problems and conduct disorders. Therefore, both bad habits and bad, violent conduct run in the family.

Study author and research scientist Jennifer Bailey warned that "children of smokers, heavy drinkers, or marijuana users are more likely to have behavior problems when they are young, and consequently more likely to have drug problems themselves as they get old. These children then grow up to be adult substance users, whose kids have behavior problems and the cycle is repeated."