The accumulation of scientific data can conflict with theoretical propositions, requiring their revision. Ptolemy's model of celestial motion was repeatedly "upgraded" until the paradigm fundamentally changed. Today, we not only understand the structure of the solar system but also see the universe across fourteen billion lightyears. Similarly, phenotype-based medical genetics still operates with concepts such as dominance, recessiveness, penetrance, expressivity, complementarity, epistasis, and so on. These are descriptive terms of limited accuracy, which are redundant and often confounding in clinical settings. This opinion article re-examines the relationship between molecular inheritance and its phenotypic manifestations in light of the growing role of gene editing and gene therapy. We believe that the use of the classical terms “dominant” and “recessive” in a medical context should be avoided as non-informative and possibly misleading in terms of clinical decisions and treatment choices.