BPD very often goes hand in hand with childhood mental and physical abuse and the death or complete lack of a parent.

In my case, mom died when I was 4 and I never knew dad. Still have no idea who he might be and at almost 30 I'm not really *that* interested.

A lot of times I try to avoid the thought or not talk about it (often thinking that I bring it up too much or that people would think I'm "milking the tragedy"). 
Yet, and I'm sure those who share the experience know the truth of this-- having an absent parent can fundamentally alter your everyday life and how you see yourself in the world (although BPD alone does that pretty well).

If you're comfortable, share your story? 