Aunt Alexandra thinks that families have certain traits that are passed down in their bloodlines. These make some families good and others bad. She believes that the Finches are one of the good families.
She says that this means that Jem and Scout must act in certain ways that are appropriate to upper crust people.
Atticus tells them to forget it because he does not want them acting as if they are better than other people just because of who their family is.
I totally agree with Atticus. Being part of some family is not important to your character. It is who you are that matters.
Aunt Alexandra's expression of her attitudes underscores the theme of prejudice vs. tolerance in Harper Lee's To Kill a Mockingbird. Her remarks about breeding and family demonstrate her class biased attitude in contrast to Atticus Finch, who finds much goodness and dignity in the characters of Mr. Cunningham, a man who pays his bills in fruits and vegetables, and Mr. Dolphus Raymond, who flaunts social taboos.
Atticus Finch does not perceive any social delineation among high society and the good. He tells the children to not pay too much attention to Aunt Alexandre's claims and, instead, look for the dignity of character within the person. To do otherwise, is an act of stereotyping, Harper seems to be saying.
The Finches have traditionally been a well-to-do and well-respected family. In fact she says that Jem and Scout are poducts of "gentle breeding" meaning that the Finches have carefully married in the past to make sure they would be upperclass and that they would have certain high society characteristics. (This tells us something about their mother too.)
We readers are under the impression that Alexandra coerced Atticus to talk with Jem and Scout and explain this. He couldn't. "Good" can be defined so many ways. "Fine" is another non-specific word. What Atticus sees in good, fine folks is people who are respectful, care for others, and take responsibility for themselves. To Aunt Alexandra, its all about your clothes, your looks, your friends, what you do. It's like she's still in high school or something.
The aunt believes that traits are passed down through the bloodlines and she wants Jem and Scout to behave appropriate to their gender and how society works. Atticus tells them not to believe in her because if the children act how society wants them to, then they will never be able to be themselves and says breeding has nothing to do with how someone will act.
Alexandra thinks that families have certain traits passed down through bloodlines. The reader gets this from Atticus who says “‘… Aunt Alexandra was of the opinion, obliquely expressed, that the longer a family had been squatting on one patch of the land the finer it was”’ (Lee 130). She tells Scout and Jem that they need to act in certain ways that are certain ways that are appropriate to their class. Atticus says ‘“I had received the impression that Fine Folk were people who did the best they could with the sense they had…”’ (Lee 130). Atticus believes people are how they are and that breeding has nothing to do with it. I agree with Atticus that breeding has nothing to do with how someone acts. Atticus tells the children to forget about it because she does not want them acting snooty.