Where are Darla's parents?

I, myself, had been wondering this, as the apparently young actress has only Max to look after her. And being the sociopath that is, you'd think her parents would strictly discipline her if they WERE around (unless they were just as evil, though I seriously doubt that, as Darla's villainy was triggered by personal selfishness towards the animals).

Just now, apparently, someone asked the same question on TV Tropes. I had always thought, however, that this would make a good plot point for a sequel.

Is Darla an orphan (who was taken in by Max), her parents are away on business (and thus Max takes care of her), or is MAX her biological single father, and yet, curiously, Darla doesn't call him "Daddy", and he is treated like a servant vs. a parent...

Either way, the lack of apparent parents could be part of the reason behind Darla's sociopathy (which my aforementioned sequel idea might decide/build around)...

Any other theories?