This is a scene from the movie Southpaw:
Judge: The child has no other family, is that right?
Attorney: Uh, no, Your Honor. Uh, both my client and his wife came up through the system.
Judge: I see. So that's why these circumstances are a little bit more painful for you.
In a child custody case, the attorney replies to a judge's question about the child's family members by saying both parents "came up through the system". What does it mean? Both parents went through foster homes? Why "came up through"?