This is a great question!
Pre-teen daughter is making mom and step-dad's lives a living hell.
Mom decides to make father take her.
Father and step-mom don't want her because of the problems she causes.
Step-mom emails me -- can we be forced to take her?
But, thinking outside the box, I had some other thoughts. This child is in crisis. Something needs to be done. How horrible that either biological parent wants this child in their home!
That is a red flag that something is seriously wrong.
I suggested (1) family counseling for parents and steps (2) sending kid to boarding school (3) sending her to live with another relative that wants her or (4) as a last resort, giving custody of the kid to CPS.
I don't like bringing CPS into the case but I've seen parents voluntarily turn their kids over when they are totally out of control. I suspect that no one wanting you must horrible. However, if the kid is out of control, on drugs or alcohol, running away from home, physically hurting themselves or others, there might not be any other choice.