ABSTRACT
One might argue that fertility behavior is more closely related to ethnic and linguistic groups than to administrative boundaries-such as republics-and therefore should be studied according to these characteristics (Chapter 1). However, such studies of ethnic and linguistic fertility differentials can only be done for census years or based on special surveys. For information on single years one has to suffice with the republics. Despite all ethnic enclaves and mixing of different nationalities,
in the same republic, there was a strong connection between the structure of the republics and the national composition of the Soviet Union. Furthermore the recent breakup of the USSR has made the republics by far the most important political units.
