Did the 1991–1995 Wars in the Former Yugoslavia affect Sex Ratio at Birth?

Proportion of males at birth (commonly referred to as the sex ratio) has been investigated for countries of former Yugoslavia that were affected by the 1991-1995 wars. Number of live births for Slovenia, Croatia, Bosnia and Herzegovina with Serbian Republic, and Serbia and Montenegro were obtained from the official vital statistics data and analysed with the Chi-square test. Results yielded no difference in the sex ratio associated with the war for the entire data set. However, country level data analysis revealed a significant increase in Bosnia and Herzegovina with the Serbian Republic, where proportion of male births during the wartime reached as high as 0.523 (compared to 0.516 in the pre-war and 0.515 in the post-war period). Countries that were involved in either mild or intermediate level of warfare did not exhibit a significant increase in the sex ratio (e.g. Slovenia and Croatia). Although war in Croatia lasted a year longer than in Bosnia and Herzegovina, analysis of the most intensive wartime periods in Croatia did not yield significant change. It seems that a hypothetical threshold of the warfare intensity combined with duration has to be reached (e.g. as in case of Bosnia and Herzegovina), in order for war to influence the sex ratio.