Board Thread:Spoilers!/@comment-2153169-20140908192157/@comment-9445918-20141012101429

DarlingDavies wrote: Hmcooper4 wrote: I think that the way I read that is that anything that is truly considered as canon from Frozen is set, and won't be twisted. So the fact that the King and Queen RAISED Anna and Elsa can not be changed. But, there was nothing ever definitive said about whether the King and Queen were the Natural Parents or not.

^This.

In FROZEN, They totally implied the fact that Anna and Elsa are pure sisters (Which means they have the same parents) and Besides the SNOW QUEEN is Anna and Elsa's AUNT! :P