geneticist /d͡ʒəˈnɛt.ɪ.sɪst/ noun2 •A scientist who studies genes. •A physician who diagnoses, treats, and counsels patients with genetic disorders or syndromes.The geneticist said Ryan had a rare genetic disorder called mucopolysaccharidosis I, or MPS I, with a wide-range of symptoms affecting multiple systems in the body. — 2017 formsgeneticists