'Delay discounting' is the tendency, given the choice, to take a smaller reward that is available immediately, instead of a larger reward that will be delivered in the future - and that is a trait that can be inherited.

Yes, your impulsive nature can be blamed on your parents, according to a report presented today at the American College of Neuropsychopharmacology annual meeting. If you need an excuse for spending too much on things you don't need, just say your delay discounting is in your genetic makeup. 

In a study of 602 twins, Dr. Andrey Anokhin and colleagues at Washington University School of Medicine found that delay discounting gradually improves as teens get older, such that 18 year-olds have a greater ability or tendency to wait for the larger delayed reward, as compared to younger teens. Apart from age, genes accounted for about half of the difference among individuals in their level of delay discounting. Many genes are likely to influence delay discounting; and some of Dr. Ahokhin's preliminary data suggest that these 'impulsivity genes' may include genes coding for enzymes that synthesize the neurotransmitter serotonin and receptors where serotonin binds in the brain. 

While it is tantalizing to speculate that the associations between delay discounting and serotonin-related genes may ultimately point the way to new treatments for addictions and other disorders involving impulsive choice, Dr. Anokhin cautions that "it is very early to link this speculation to a clinical application."