Sounds like your average run of the mill teenager.
A young parent who's too stupid to use condoms when banging 50+ schoolgirls a year and flaunting his immaturity like a status symbol. Playing violent games no matter what anyone thinks. And watching porn every single night when he can't convince a schoolgirl to "have fun" at his place while the girl he knocked up takes care of the baby by herself.
But this one did something out of the norm by committing murder, so lets not look at the parents since they did keep him in the norm best they could.
There must be some other reason for it.