Fio is appalled by the assertion that because Casey Anthony is a liar and probably a murderer, her family must have done something awful to her when she was a child. Fio won't hazard a guess as to why Miss Pout Face is the way she is, but she doubts that supposed sexual molestation (such an easy accusation to throw into the pot) had anything to do with it.
Fio herself used to believe Nurture was overriding. But, TV stereotypes to the contrary, she now thinks Nature, what is born into a person, is also very important, and some people are born with problems too big for any parents to cope with.
And, by the way, does Casey herself know who her child's father was?