“He’s just like his father” comment many mothers. Though there is not always an evident hereditary link, researchers agree that A.D.D. is a neurologically based disorder that is genetically determined. Evidence for genetic factors comes from studies of twins, adopted children, and other family members. Currently there is exciting research going on that may identify more precisely the genetic mechanisms that operate in some people with A.D.D.; for example, a particular variation in the chromosome that controls dopamine-4 receptor sites in the brain (dopamine is one of the neurotransmitters) was found to occur more frequently in people with A.D.D. Parenting style is important in terms of how the inborn temperament develops but it does not produce the basic A.D.D. symptoms. Keep in mind that the likelihood is that the father of the child with A.D.D. survived, and perhaps even thrived, without any label, diagnosis, or treatment. These parents, and it can be either mother or father who shows the traits, are often entrepreneurs or successful in sales and have used their high energy and hyperfocus to their advantage.