When I taught this spec I covered all 3 areas but only so I could be confident that they would have enough information and also the students found this section really interesting! As there are no references made to any specifics of sex role stereotyping in the spec, an exam question cannot focus specifically on one area. It has to be more general. (I'm sure someone will correct me if I am wrong here). I'm not entirely sure about 'discuss research'.I would teach 2 studies just to be on the safe side. Perhaps email the Psychology person at AQA (It was Nicola Templeton, I'm not sure if it still is) and ask. If you PM me your email address I can send you some stuff as well, if that would be of any help!