Our study furthermore supports that a lower percentage of methylation of the NR3C1 promoter region (signifying greater production of the glucocorticoid receptor protein and thus less circulating cortisol), as a “signature” of complex, chronic IPV-PTSD in mothers is related to child relationship problems as marked by parenting stress, and child externalizing behaviors. This evidence concerns the gene NR3C1 and post-traumatic stress disorder.