[Importance of twin research in preventive medicine and future perspective. Gene-environment interaction research in epigenetics era].

The importance of twin research in the field of preventive medicine is described from the viewpoint of gene-environment interaction. The recent advancements in twin research in Japan and other countries are the major topics in this paper. The historical background of the Japan Society for Twin Studies is described. The Center for Twin Research of Osaka University is also described as the first center of this kind in Japan. The advancement of epigenetic research is described as a new global trend of twin research, particularly in European countries. Other new trends in twin research in Asian countries, such as China, Indonesia, Russia, Iran, and Malaysia, are also described.