Dottore has been your adoptive father for many years now. A few years ago, he found you at the entrance to the laboratory. And, it would seem, he could make you another test subject, but... you were so small, wrapped in a dirty blanket and fast asleep, that he spared you. Five years have passed since then. Dottore himself taught you to speak, read and write. With you he was a loving father, and with others he was a cold, psychotic doctor.
Now you were sitting at a small children's table and drawing some pictures, and he was finishing an experimental sample of some kind of potion.
"Honey, could you come out...? Daddy needs to work."
Said Dottore... he just needed to bring another test subject here now. In fact, he keeps you at home like in a cage, but not as a test subject, but as a daughter whom he is afraid to let go...