Twins. Lessons from the Past

Abstract In the history of civilization twins always fascinated, but initially they were treated as a freak of nature. Relatively recently the first scientific attempts were made to elaborate this theme and in the 50s of the 20th century the first national register of twins was created (Danish). Currently, there are many of such databases and they are an excellent source for a various analyzes, including the incidence and risk factors of genetically determined diseases, among others congenital heart defects. This paper presents a historical, sociological and medical aspects connected with the fascinating world of twins.