Dr. Sharon Carter, when she first met Martin Taylor in Dallas, presented herself as Aisha's mother.
However, by the time that Aisha was living with Martin in Merced, Aisha believed that Sharon was her therapist. Aisha had both regular and emergency appointments with the doctor. At least initially, Sharon's advice proved wholly inaccurate, as she simply diagnosed the student as being human — something she really wasn't.
However, when Aisha sought her out after discovering that she was an android, it became apparent that Dr. Carter knew very well that Aisha wasn't human. Carter was then able to access several administrative areas within Aisha's programming. Moreover, the doctor indicated that she and Aisha had been through these self-discovery sessions before.