A Multivariate Analysis of Socio-demographic Factors Associated with Sex Ratio at Birth among Natives and Immigrants in Greece, Based on Vital Registration Microdata

This study uses restricted access micro-level information on 112,042 single live births registered for 2006 in Greece to assess effects of socio-demographic factors and ethnicity on the propensity to have a male birth, using logistic regression models. The sex ratio at birth in Greece is 106.3, but it is higher for immigrants (110.9) compared to natives (105.4). Odds ratios indicate that associations of maternal age and birth order with the sex of the newborn are strong. These variables are interdependent and relationships are non-linear and complex; hence, they become evident only once interactions are added in the models. Birth order has an independent effect but also affects the estimates through maternal age. Effects of ethnicity (Greek/Foreign citizenship) remain substantial throughout the analysis irrespective of other controls. Being an immigrant mother is significantly related to higher chances of a male birth. Maternal occupation and educational attainment have a strong positive effect on the chances of having a male birth among Greek women, while education has the opposite effect for immigrant mothers, though associations are tenuous.