When in chapter 13 of To Kill a Mockingbird, Atticus is trying to inform Scout and Jem about the Finch family, he says he is trying to tell them the facts of life. Jem responds by saying that he knows "all that stuff." What stuff does he mean? Sex?
In chapter 13 of Harper Lee’s To Kill a Mockingbird, Aunt Alexandra has come to stay with the Finch family for a while. The purpose of this visit is to give Aunt Alexandra a chance to exert some “feminine influence” on the children, who are being raised by their father Atticus, with a lot of help from their African-American housekeeper Calpurnia.
The problem with this arrangement is that Alexandra is nothing like her brother Atticus. She is rigidly conformist and moralistic. She places social standing and the reputation of the family above all else. She believes that Atticus is not doing a good enough job raising the children and constantly hounds them to behave properly and uphold the good family name.
Atticus, probably out of a feeling of guilt, goes along with the plan for a while. Late in the chapter, when he is talking to Scout and Jem alone (outside of earshot of Aunt Alexandra), he steps out of character and tries to tell the children to behave the way that Alexandra wants them to. He is clearly uncomfortable doing so. When Jem asks, “What’s the matter?” Atticus says:
I’m trying to teach you the facts of life.
Jem misunderstands Atticus, who probably chose his words poorly for this situation. He is struggling so much because he does not believe in what he is saying to his kids—his parenting style is much different than Alexandra’s; he almost treats his kids as equals who just need advice to learn how to live properly, while Alexandra treats them like formless globs of clay that must be molded into the desired form.
After Atticus makes the statement above, Scout narrates:
Jem’s disgust deepened. “I know all that stuff.”
We can tell by Scout’s choice of words here (“disgust”) that Jem probably thinks that Atticus is talking about the “birds and bees.”
But that is not what he means. Atticus goes on to try to explain things the way Aunt Alexandra would, telling the children how they should behave to honor the family name.
When he sees how Jem and Scout react negatively to his sudden change, he drops the whole thing and goes back to being himself. He finally tells them to “forget it.”
The chapter concludes on a humorous note when Scout, now narrating as an adult, explains why the attempt to re-socialize them was doomed to failure:
I know now what he was trying to do, but Atticus was only a man. It takes a woman to do that kind of work.