DRD4 and attention deficit-hyperactivity disorder: To test this hypothesis, we used a large previously collected sample of ADHD children to examine the impact of: (1) being male (73), (2) carrying at least one copy of the DRD4 7 repeat allele (92), (3) having comorbid mood disorder (93), (4) having comorbid anxiety disorder (93), and/or (5) having reduced right-sided motor dominance (69, 70) on rightward parietal EEG asymmetry, and whether this phenotype is associated with ADHD symptoms.