Genetics had already proven its importance in art of knowing about the species from the basic cells of reproduction and also about the various features that a species adopt from his ancestors. Thousands of inherited human disorders have been catalogued to date, but the underlying genetic causes of less than 20 percent of those disorders have been discovered. Genetics is the study of genes at all levels from molecules to populations. In dentistry we encounter numerous differences in the dentofacial characteristics of individuals, even among family members.Some children have large-size teeth; some may have high prevalence of caries, while only some have good occlusions. Is dental health inherited? Common dental diseases such as dental caries, periodontal diseases and malocclusion problems are often considered mainly as environmental. However in these diseases the genetic aspects that influence the degree of susceptibility should not be overlooked. Today genetics is a mature but dynamic science, clearly in its prime and recognized as the very core of modern biology.