In direct contrast to her more liberal brother, Atticus, Aunt Alexandra represents the conservative values of the Old South, including the idea that blacks and whites should stay away from each other, and that some families are better than others. When she comes to stay with the family the summer of the trial, these differences in philosophy are apparent almost immediately when Scout requests that she be allowed to visit Calpurnia's home someday. Atticus likely would have relented, but Alexandra's stern voice punctuates the scene as she thunders, "You may not!" at the little girl. Another difference in opinion is seen in Alexandra's opinion of the poverty-stricken Cunninghams, which is not favorable (she refers to them as "trash"), while Atticus has taught his children the dignity of Walter's family refusing to take a handout from anyone.
Alexandra's primary barometer for determining which people constitute "good families" like her own generally comes down to whether or not the family has been in the area a long time, and whether or not people have made favorable matches when marrying, implying that Scout and Jem's mother must have fallen into this category when she states that Jem and Scout are the result of "gentle breeding". Ironically enough, there is something less than "gentle" in the background of the Finches, as Scout observes at the novel's beginning, commenting on her father's place in the community and their ancestor, Simon Finch:
He [Atticus] liked Maycomb, he was Maycomb County born and bred; he knew his people, they knew him, and because of Simon Finch's industry, Atticus was related by blood or marriage to nearly every family in the town.
If Alexandra knew that part of her family's history, she sure did not mention it when asking Atticus to talk about the family's place in Maycomb!
At one point, Alexandra implores Atticus to have a visit with the children and try to explain some of these things about their background so as to encourage them to live up to the family name in actions, words, and general behavior. The conference between Atticus is a fiasco; Atticus, probably recognizing from the beginning that it was a silly conversation, got frustrated and snapped at Scout, which made her cry. He gave up, told the kids not to worry about it and made a joke on his way out of the room about one relative's activities that Aunt Alex did not want to discuss.