We also see Mary's softer side in her relationship with Jess and, occasionally, with Carrie. Having lost her mother at a young age, she is constantly motivated by a desire to keep her daughter and younger sister safe, ostensibly from the corrupting influence of Dean, but ultimately from anything which falls outside the system of beliefs with which she cushions herself. On top of her similarities to Dean, Mary's character is made more paradoxical when we find out, despite her insistence that Jess stay away from boys, that she had her daughter at seventeen. In reality, this was written in to fit the ages of the actors – but as with Carrie/ Claudette's pregnancy, it seemed to add to rather than detract from the story.
If you think Mary's portrayal is especially convincing when you see Giving up the Ghost,you might be interested to know that actor Mary-Jo once wanted to be a nun, and brought her daughters up for many years as a single mum – just like Mary did.