Well, I guess the writers had to make a choice among the offspring. Of Vito's children, who would you think would produce a child with the characteristics to get involved in the family business. I'd pick Sonny. Mike's kids went with Kay eventually; Connie's kids? Well hell, she never showed any aggression except in that scene at the end of GFI in Mike's office. And you could never have an Irish Don, could you?