Childhood Abuse: Does it matter which parent is the perpetrator?

Childhood physical abuse is, of course, related to many negative outcomes, affecting relationships, health, neurobiology, substance use, and mental illness

Does it matter which parent commits physical abuse? In some cases, it may not. One recent study found no significant differences in mental health outcomes depending on whether the mother, father, or both parent were the perpetrators of physical abuse.

It is unclear how this finding relates to who the child is living with. If a child splits his time between two homes and only one parent is abusive is the effect the same? What if the parents live together, and one parent witnesses the abuse and refuses to intervene?