THE CHANGING SEX RATIOS AT BIRTH DURING THE CIVIL WAR IN TAJIKISTAN: 1992–1997 SOPHIE HOHMANN*, SOPHIE ROCHE†  MICHEL GARENNE‡ *EHESS and INED, Paris, France, †Max Planck Institute for Social Anthropology, Halle, Germany and ‡IRD and Institut Pasteur, Paris, France Summary. Sex ratios at birth are known to change during wars or shortly after. This study investigated changes in sex ratios during the civil war that occurred in Tajikistan after the dismantling of the Soviet Union. This civil war was particularly bloody and long lasting, and had many demographic consequences. According to vital registration data, some 27,000 persons died in excess of previous trends during the civil war period (1992–1997), and total mortality was sometimes estimated to be three times higher by independent observers. Birth rates dropped markedly during the war, and sex ratios at birth increased significantly from 104.6 before the war to 106.9 during the war, to return to baseline values afterwards. The change in sex ratio is investigated according to demographic evidence (migration, delayed marriage, spouse separation), substantiated with qualitative evidence (difficulties with food supply), and compared with patterns found in Europe during World War II, as well as with recent wars in the Middle East. Introduction Variations in the sex ratios at birth (defined as the ratio of male births to 100 female births) have been the focus of numerous debates in the demographic and biologic literature (Süssmilch, 1761; Ciocco, 1938; Gini, 1951; Visaria, 1967; Teitelbaum, 1970; James, 1987; Chahnazarian, 1988). A feature of sex ratios is that they often change during – or shortly after – wars, as is the case for other demographic parameters, in particular birth rates, death rates and marriage rates. This has been documented for a long time in France (Aubenque, 1989), and in Europe, and has been reviewed recently in detail (Graffelman & Hoekstra, 2000; James, 2009). For comparative purposes, the data from France were re-examined using vital registration statistics, which are available in the Human Mortality Database (2009). During the First World War (WWI), major changes in natality occurred: birth rates dropped for six years, and increased in 1919–1920 as a result of postponed marriages. The sex ratio at birth did not change during the war: it averaged 104.6 in 1914–1917, and thus was equal to the average of the previous years (1904 to 1913). However, it J. Biosoc. Sci., (2010) 42, 773–786,  Cambridge University Press, 2010 doi:10.1017/S0021932010000337 First published online 12 July 2010 773