This study investigates the function of the hypothalamic-pituitary-adrenal (HPA) axis in adolescent antisocial girls. This question is important because disturbance of HPA functioning has been found in populations of violent adult males and antisocial adolescent males, suggesting that it may be a marker of a physiological disorder associated with antisocial behavior. The investigators examined 228 pregnant or postpartum teenage girls, categorizing them as having conduct disorder (CD) or not having conduct disorder (NCD). HPA axis function was assessed with saliva cortisol samples obtained in the midmorning when the girls were 4 and 9 months postpartum. The hypothesis was that girls with CD would have lower cortisol levels than girls without CD. The investigators did not find any significant difference in cortisol levels between the two groups, an important but puzzling finding. Azar et al. suggested that this result may demonstrate a lack of clear HPA axis involvement in antisocial mothers.