Both maternal depression and dopamine-related genotypes have been linked to the development of the HPA axis. This thesis explored whether and how DRD2, DAT1, and (from an exploratory perspective) COMT genotypes moderate the relation between maternal depressive symptoms and infant cortisol reactivity in the context of a toy frustration challenge at 16 months and in the context of a maternal separation challenge at 17 months. Buccal cells were used for the purpose of genotyping. Maternal depressive symptoms were assessed via self-report at infant age 16 months. Candidate DRD2 and DAT1 genotypes moderated the relation between maternal depressive symptomatology and infant cortisol secretion in a diathesis-stress manner in the context of the toy frustration task, and in a differential susceptibility manner in the context of the maternal separation. Results are interpreted as indicating that the nature of gene-environment interactions is context-specific.