The meaning of this difficult and painful novel is obvious from the plot: Not only is living a life by fear and shame a disastrous mistake, it is also extremely abusive and painstaking to raise one's children to behave according to shame and fear. This takes a religious flavor, because of the parent's hyper-religious attitude in life, but the daughters' decision to be religious was always just a thinly veiled way to impress their parents by adopting their point of view.
The parents point of view is therefore worthy of analysis, because that is where we will see what kind of shame system the girls adopted to leave them with suicidal depression and repression. The answer lies in the way the parents subject themselves to shame in the guise of religious language. By focusing on sin and mistakes, they offer their daughters a one-sided narrative. Not only should they understand the risks of guilt and shame, they should understand the rewards of experimental behavior—the development of the self and the progress of the soul.
Not only do we change by experience and growth, we are biologically programmed toward certain kinds of behavior, which is part of why Eugenides is so stark and firm in his rejection of shame. Shame is a way of teaching each other to be embarrassed and afraid of our own instincts and growth through time.
Another way of thinking about this is this way: Like a pet owner might watch a dog's life cycle from puppy to dog to older dog, to eventually death, so also humans are simply observing the life cycle of the body, and adding religious shame to that process will leave humans unable to succeed, because religious scrutiny will be applied to natural processes. In less technical language, shame is useful as a tool, but as a master, a person will become undone by shame and fear, because with shame constantly lurking over one's shoulder, they might not have the bravery to continue forward in their development as a person.
