Somatic gene therapies may be authorised for marketing in the EU under the advanced therapy medicinal product regulation. These therapeutic compounds are sufficiently novel and complex in their potential effects to require specialist evaluation. However, the current definition of gene therapy medicinal products ('GTMP') risks excluding molecules which are not manufactured through techniques involving recombination. We consider the way, in which the 'recombinant nucleic acid' aspect of the GTMP definition is challenged by developments in gene-editing technology, and why a broader scope of GTMP regulation may be desirable.