Examining this article carefully, it's quite clear that the son was always going to rebel.
You can see from his photo that he has a worldly hairstyle (rather than a sophisticated comb-over like his father) and, of course, he's smiling.
And it's all his mother's fault - if you look at the photo of the parents in zombieland you can see that she's on a completely different page to the other two, showing dangerous individuality.
(The box advert for 'forthcoming attractions' made me smile. 'Why be truthful?' Indeed.)