Birth Order and Sibling Gender Ratio of a Clinical Sample of Children and Adolescents Diagnosed with Attention Deficit Hyperactivity Disorder

Objective: it is not clear whether sibling’s gender ratio is associated withattention deficit hyperactivity disorder (adhd). this study examineswhether inattentiveness severity and hyperactivity/impulsivity severity areassociated with birth order of children with adhd .method: participants are a clinical sample of 173 children andadolescents with adhd and 43 ones without adhd. diagnoses weremade using diagnostic and statistical manual of mental disorders forthedition-text revision (dsm-iv-tr), diagnostic criteria according to faceto-face interview with the children and their parents. adhd dsm-ivchecklist was used to measure inattentiveness andhyperactivity/impulsivity scores .results: the association of birth order and diagnosis of adhd was notstatistically significant after adjusting for covariate factors. the genderratio of siblings is not associated with adhd.conclusion: birth order and siblings gender ratio are independent of adhd diagnosis. the results of this study support the fact that genetic factors rather than environmental factor of birth order is associated with adhd. moreover, contrary to autism, the current results do not suggest the androgen theory for adhd.