My mother had borderline-personality disorder, and I strongly suspect PTSD. She was a very, very messed up woman. She had a heart of gold, but living with her was in and of itself often traumatic. We were very close - I loved and still dearly love my mother - but I have also recognised how imperfect she was and how much damage she caused me. She died when I was 17 (I'm 32 now).
As for my father... I never grew up with him, he was never in my life except for random visits that were over in less than an hour. He has many problems that stem from his childhood. I only know this because I worked up the courage to meet him properly for the first time when I was 27. Doing so opened up so many wounds I hadn't realised I had; I became extremely unwell and unstable as a result of being confronted by my father's past, about the fact that he abandoned me as a baby in favour of pursuing his own leisures, and things he knew about my mother that I never knew.
Both sides - mother and father - experienced intense childhood trauma. It's no wonder they were (and are, in my father's case, as he's still alive) so messed up.