We Need To Talk About Kevin film tie-in

Two years ago Eva Khatchadourian's son, Kevin, murdered seven of his fellow high-school students, a cafeteria worker and a popular teacher. Now, in a series of letters to her absent husband, Eva recounts the story of how Kevin came to be Kevin.
Fearing that her own shortcomings may have shaped what her son has become, she confesses to a deep, long-standing ambivalence about both motherhood in general and Kevin in particular. How much is her fault? When did it all start to go wrong?
Or was it, in fact, ever 'right' at all?