What happens if both parents are under investigation by the same children's aid society at once?

When both parents are under investigation by the same children's aid society at the same time, the society will typically assess each parent's home and circumstances separately, even though the same worker or file may cover both, since the question in each case is whether that specific parent's home is safe for the child. It's possible for the society to have concerns about one parent, both, or neither, and for the outcomes to look quite different even though the investigation arose from the same file or incident.

For the parents' own family court case, this situation doesn't automatically favour either side - each parent's outcome with the society is relevant on its own terms, and one parent shouldn't assume that simply "also being investigated" cancels out a more serious finding against the other. If interim decisions about where the child stays need to be made while both investigations continue, the family court, the protection court, or the society may need to consider whether a suitable third party, such as extended family, should care for the child temporarily instead of either parent, depending on what the concerns actually are. Get legal advice specific to your own investigation rather than assuming the other parent's situation determines yours.