What are three lessons taught by the characters in The Chrysalids?

From David we can learn to be open-minded about the world and the people in it, and not blindly follow the will of our parents.  Children are definitely impacted by their parents’ beliefs.  Parents raise their children with a moral code.  However, sometimes children grow up to question that code. 

This was the case with David.  His father was strongly religious, but he realized that just because someone is different does not make them a mutant, ungodly, or worthy of rejection.  He befriended Sophie despite her extra toes, even though not turning her in was a crime.

I certainly did not feel unusual. I was a normal little boy, growing up in a normal way, taking the ways of the world about me for granted.  And I kept on like that until the day I met Sophie. Even then, the difference was not immediate. It is hind-sight that enables me to fix that as the day when my first small doubts started to germinate. (Ch. 1) 

David’s relationship with Sophie helps him to better understand himself.  Both of them are mutants, even though David is certified.  His difference is not visible.  He is a telepath, meaning he is one of a small group who can read minds.  This would make him blasphemous too if anyone knew. 

Another person we can learn from is Anne.  Anne’s story is truly tragic.  She marries Alan, a man who is not only not telepathic but also strictly religious.  He is the one who turns Sophie in.  She knows that he would turn anyone in easily and not think twice about it, but she fell in love with him.  You can’t control who you love.  Yet Anne teaches us that we should take care in who we choose.  Things do not just work out because we want them to. 

I'm not a fool. Of course I've thought. I've thought more than you have. I'm a woman — I've a right to marry and have children. There are three of you and five of us. Are you saying that two of us must never marry? Never have any lives or homes of our own? If not, then two of us have got to marry norms. (Ch. 10) 

Anne makes a bold choice, with disastrous consequences.  She ends up killing herself.  Sometimes we take chance on love and it doesn’t work out.  When she finds Alan dead, she blames the telepaths.  She kills herself and leaves a note renouncing all of the telepaths. 

Sophie’s parents are the last characters we can learn from.  They hide their daughter and protect her, even though it is dangerous for all of them.  They do not care, because she is their child.  From them we can learn the value of protecting people you love, no matter the consequences.  If someone hadn’t spotted the extra toes, how would anyone know she was different?

David ponders the extent of a mother's love.

And Aunt Harriet had been more than ready to break the Purity Laws. So had Sophie's mother. It made one wonder how many mothers there might be who were turning a blind eye towards matters that did not actually infringe the Definition of the True Image — and perhaps to things that did infringe it, if the inspector could be dodged. (Ch. 12)

David's Aunt Harriet had tried to hide her baby when it did not conform.  She wanted David's mother to lend her Petra so she could get a certificate.  David's mother turned her away.  David wonders if she would given up David and Petra if she knew, or how she will feel when they are caught.