This review offers a critique of recent attempts to reconceptualize some cases of borderline personality disorder (BPD) within the newer diagnosis of complex posttraumatic stress disorder (CPTSD). The CPTSD construct focuses on the role of childhood trauma in shaping relational problems in adulthood, difficulties that have been previously seen as features of a personality disorder. The CPTSD model fails to consider the role of heritable personality traits, as well as a broader range of psychosocial risk factors. This review proposes that a biopsychosocial model of BPD is more comprehensive, taking into account a wider range of risk factors, while viewing BPD as rooted in gene-environment interactions. In this model, heritable traits are amplified by an adverse psychosocial environment. One can acknowledge the role of trauma as a risk factor without assuming that it fully accounts for the development of personality pathology.