Although I see exactly what some of you are getting at in your posts, do consider that your experience and that of your family isn't the same as everyone else's. People can be born with PDs, or they can be formed through abuse, neglect, etc. if they have a predisposition to the disorder. This is hard to prove, but it has happened almost spontaneously in certain cases.
There are many mental health disorders that follow that line... mine is an example although it isn't a PD. I'll use it anyway, though. I went through a deep depression for several years in my late teens and early twenties. After I finally got help and discovered what was wrong with me (and got better

), my cousin told me, "oh yeah... sorry about that--we should have warned you." I had little contact with my birth father or his family growing up, but apparently it is a consistent pattern for the women in that family to go through depression in their twenties (usually late 20s, but a couple of people very close to me died in relatively quick succession in my late teens which brought it on early for me). They all have gone through it in one way or another, but it had nothing to do with the way I was raised since they weren't part of my upbringing.
PDs are much the same... a predisposition can be triggered by events, you can be abused to the point of developing one, or you can "just happen" (the most frightening choice of all). We don't want to believe that it's possible for this to happen for no reason because it takes away the control we think we have over our lives. Your child might have ASPD for no reason, or turn out with HPD just because... it totally sucks, I know. But it happens, and that's what all the books say.

Sorry to be the party pooper.