asked her a about male sexuality? since she is a doctor.But she replied nothing about the question by saying that she doesent know much about it.I asked her because i felt that she knows alot than me about it.After some time she aaked me to delete that message so that my younger sister could not see it. Even i stopped talking about it after sometime becayse of the feeling that she is getting uncomfortable.Can anyone tell me why she behaved that way......I know that she is my sister and all of the above she is a medical student.I am a brother of two sisters.