What evidence suggests that the Waknuk society is obsessed with eliminating any kind of "mutations" in The Chrysalids?
In Waknuk they are very concerned with preventing any kind of deviation. All residents have to have a certificate proving they are produced in God’s image with no deformities of any kind. Even animals and crops that are not perfect are destroyed.
A highly religious society, the people of Waknuk seem very concerned with deviation.
ONLY THE IMAGE OF GOD IS MAN. .. KEEP PURE THE STOCK OF THE LORD… BLESSED IS THE NORM, and IN PURITY OUR SALVATION. .. WATCH THOU FOR THE MUTANT! (Ch 2)
In addition to the strongly worded signs, there are also severe consequences for deviation. When Aunt Harriet has a baby that has a little defect of some kind, she tries to borrow David’s baby sister so no one will know and she can get a certificate clearing the baby. She reveals that she has had three.
This is the third time. They'll take my baby away again like they took the others. I can't stand that -- not again. (ch 7)
In the case of Sophie, her parents have somehow managed to hide her. No one knows about her, because she has six toes. If anyone discovered this, she would be expelled.