In the movie The Orphan what is the orphans secret?

[Catherine]

i want to see it but i can't so what is her secret just tell me and i will be very happy

[Hardy]

shes actually a 33 year old psyco killer woman with some disease so she looks like a kid (seriously)

[Billy]

She's a 33 year old woman from Estonia that escaped a mental institute. She tries to secude the husbands of her adoptive family and if they reject her, she kills them.

[Federer Fan (15 Majors) T]

Her secret is that she is not really a child, she is actually an adult with some sort of disease that made her stay very small and look very young her whole life.

She was also a prostitute in the past and goes to families and tries to seduce the father. She does this to make up for her own insecurities about not being a "real woman". She is crazy.

[Bradley Bruiser Brooks]

Both her parents died, thus, she's an orphan, duh!