Generational patterns

I posted on here not long ago about an out of control teen. People were quick to comment about how it was the teens mothers fault for the teen acting that way.

I don't necessarily disagree but those comments got me thinking about generational cycles/patterns.

Perhaps the mom raised her teen that way because that's how she was raised when she was young, and was unable to change her way of thinking/acting that had been ingrained in her since childhood. Perhaps that teen will go on to raise children of her own who will also be unmanageable.

Where do we draw the line as far as who is accountable? Is the mother accountable even if she was raised in the same manner? Or are the mothers parents accountable for teaching her such things (or whichever generation it started with)? I realize many people come from unhealthy upbringings and go on to be completely magnificent people, however this particular question isn't meant to be centered around those people, but rather the others who continue the negative generational patterns.

What makes someone keep or discard the way they were raised? Once a child becomes an adult do they simply make a choice? I imagine many people might say yes, but I also figure the "choice" could be quite difficult to make of its all you've ever known and what you've considered "normal" - and if that's the case, you might not even know there is a choice to be made at all.