While there can be instances of a deviation, I still stand by my statement as I have seen it over and over again with most of my relatives, most of my acquaintances and in the case of my own upbringing, my sisters. The deviation to my argument would be in how I turned out compared to my sisters given the fact that I had, what could considered, shitty parents and a shitty upbringing. Up until I was in my late teens, my statement was 100% true, shitty parents = shitty kids. Admittedly, I was a fucking asshole growing up, period. The change in that mindset came after I had joined the military. One could argue that I was "reborn" and my mind was properly nurtured through actual discipline. As a result I saw the error of my ways and consciously decided the life I had lived through was not one I wanted for my own children. As such, I have made a conscious effort to raise my children in a more civilized manner, contradictory to how I was raised.
Not to say that my kids are 100% perfect or anything, but if the worst I have to deal with is my oldest stepson graduating a year late because of his mental disability, my daughter getting a ticket for speeding, my youngest stepson rolling his jeep when he was 17, or even my youngest son getting shit grades in his freshman year, then I think my wife and I are doing something right and sure as shit doing it better than most of the people I know.
Parenting is a lot of fucking work. A.LOT.OF.WORK and it sure as shit isn't easy, but if you're not willing to put forth the real fucking effort with your children, then odds are you're just gonna continue the cycle and perpetuate the argument that shitty parents = shitty kids.