My reading has led to a family tree search.  I think this BPD is all over both sides of our tree along with Asperger's, Dyslexia, and Anxiety Disorders.  My whole life I focused on drinking/addiction as our family pothole.  Now, I suspect mental health issues are the drivers for alcohol and drugs.  Maybe that is an oversimplification.  Anyway, hello. And thanks for being here.
Hi Candace50:I tend to agree with your logic.  I believe that genetics plays a big part in mental health issues.  From that point, how an individual deals with the cards they are dealt, can make a big difference in the outcome.  Those who don't get help or resist treatment and/or counseling, tend to use unhealthy ways to self-soothe, such as alcohol and drugs.   
Abuse & environment can be a factor, but you can't discount that the abusers are dealing with mental illness and that their children could be dealing with genetics alone or genetics & abuse.