Subjects: children (n = 241, 51 female), aged 4–16 years with conduct problems (full or symptoms of ODD or CD according DSM-IV), referred to the Australian Normative Sample as control (19). Diagnostics: DSM-IV, SDQ, DISCAP. Comorbidity: ODD/CD 66%, ADHD 26%, anxiety/depression 6%, ASD 5%. Methods: Genotyping and selective methylation analysis of NR3C1 promoter exon 1F (12 CpG sites) by mass spectroscopy. Morning cortisol plasma levels were quantified by chemiluminescent enzyme immunoassay. The gene discussed is NR3C1; the disease is Oppositional defiant disorder.