The concept of intergenerational transmission of trauma plays a fundamental role in psychoanalysis, yet its relationship to DNA has gone largely unstudied. While it is known that intergenerational trauma can be transmitted through attachment relationships, a new branch of genetics (epigenetics) was born with the goal to study the interaction between environmental factors and DNA. Due to this, it has become more evident that human behavior can physically change DNA expression. Therefore, psychoanalysis—which has proven to reduce intergenerational transmission of trauma from a behavioral perspective—can play a positive role in regulating DNA changes caused by environmental stress. The present paper focuses on recent research suggesting a direct correlation between psychological trauma and DNA modifications. In particular, that DNA changes caused by physiological trauma can be transmitted from generation to generation, validating the psychoanalytic concept of intergenerational transmission of trauma. This evidence not only supports psychoanalysis’ essential role in influencing human behavior, but also suggests that psychoanalysis impacts DNA in a way more significant than previously acknowledged. This also suggests that psychoanalysis affects not only the individual subjected to psychoanalysis, but future generations via epigenetic passage of DNA.