The effects of trauma may propagate via interpersonal psychology across several generations (e.g., when victims of childhood sexual abuse become the sexual abusers of the next generation’s children). Some experts claim, however, that the effects of trauma may propagate across generations via genetic inheritance. This claim revives a pre-Darwinian evolutionary theory, known as “Lamarckism” and oft-summarized as the inheritance of acquired characteristics, which was straightforwardly superseded by Darwinism and then neo-Darwinism. This biological theory of intergenerational trauma is, however, considerably weaker than Lamarckism. Lamarck’s original theory endorsed only the inheritance of acquired physical characteristics, whereas the biological theory of intergenerational trauma goes further in endorsing the inheritance of acquired psychological characteristics—a position that is susceptible to all the same critiques that undermine the beleaguered field of Darwinian evolutionary psychology: such as the critique that the human mind, in its creation of knowledge, routinely overrides those psychological predispositions that are encoded in the human genome. So, the biological theory of intergenerational trauma asserts the existence of two untenable kinds of genetic inheritance, both of which contradict good explanations in other fields (i.e., evolutionary biology and epistemology, respectively), and neither of which could function by any known biological mechanism. Thus, we should regard the biological theory of intergenerational trauma as false.