"moja sestra"
I wonder how many on here picked up on the reference to "The Cat People" (1942), namely Helena's referring to her clone sisters as moja sestra (pronounce the j as a y), which is Serbian for "my sister".
In The Cat People, Irena (Simone Simon) encounters The Cat Woman in a restaurant, she refers to Irena as "moja sestra" which causes shock and alarm with Irena, her fiance and friends.
If you have never seen The Cat People you will be well rewarded be checking out not only that film but the other classic B films Val Lewton made for RKO in the 40's..