The natural wonder of multiple pregnancy and birth has fascinated mankind since ancient times and twins figure prominently in legends, folktales and myths. One of the best known traditional stories is that of Romulus and Remus, the twins who were abandoned on the banks of the Tiber and suckled by a she-wolf. Later Romulus founded Rome, the city that still bears his name, after killing his twinbrother. Tales of profound attachment of co-twins, such as Castor and Pollux, as well as those of murderous jealousy, such as between Jacob and Esau, illustrate an early intuitive recognition of the fact that even identical twins have their own personality. A century ago this particular aspect of twinning made Francis Galton realize that twins could also serve as tools for scientific research into the old question of nurture versus nature. His publication "The history of twins, as a criterion of the relative powers of nature and nurture" that appeared in 1875 set the basis for the development of what is now known as the "twin method" in scientific research". The twin method in its simplest form is based on the assumption that the extent to which any given morphologic, biochemical, functional, or behavioral trait or condition exhibits a higher average within-pair similarity in monozygotic than in dizygotic co-twins is a reflection of the extent to which that particular variable is under genetic control'oo. The cause of multiple pregnancy and its clinical hazards have been subject of medical investigation since Hippocrates' time.

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H.C.S. Wallenburg (Henk)
Erasmus University Rotterdam
Organon, Ferring BV, Abbott BV
Erasmus MC: University Medical Center Rotterdam

Santema, J.G. (1996, September 25). Clinical aspects of multiple pregnancy. Erasmus University Rotterdam. Retrieved from