Can BPD be inherited? Here’s an article on the biological aspects of BPD.
Genetic studies of monozygotic and dizygotic twins suggest that there may be genetic factors for these dimensions of emotional reactivity and impulsive aggression, while there does not appear to be a heritability for BPD as a category. Family members of BPD patients are more likely to demonstrate affective instability or impulsivity, although not necessarily both. Impulsivity and aggression seem to be heritable in studies of normal twins as well. It is noteworthy that in the studies of prolactin responses to fenfluramine, blunted prolactin response to fenfluramine in a patient is a better predictor of impulsivity and aggression in their relatives than was impulsive aggression as a behavior in itself in the patient. These results would suggest that what is inherited is not the behavior, but an alteration in the serotonergic system that may at times be expressed in a propensity to impulsive aggression.
So, according to this article, it’s not BPD that’s inherited, only the traits of BPD (impulsive aggresion). On a personal note, I have twins (dizygotic or fraternal) and one seems to have the emotionality and impulse control issues, the other does not.http://www.mhsanctuary.com/borderline/siever.htm