Is there any research about adhd being a genetic disorder?

Studies: There has been considerable amount of research done addressing the hereditary aspect of adhd. The research suggests there is a strong hereditary component. In fact, adhd surpassed bipolar d/o as the #1 hereditary mental disorder research has not isolated a particular gene however.

Yes: There's a fairly clear genetic component. There isn't a particular gene that had been identitified, but a review article from 2010 estimated that genetics is responsible for about 75% of the risk for adhd. There have been over 1800 scientific studies looking into the genetics of adhd.

Absolutely: See my health files for a paper by faraone & biederman about the high heritability of adhd. There are hundreds of studies indicating the genetic concordance of adhd.