title: Secular trends and geographical variations in sex ratio at birth.
abstract: Numerous studies have established the presence of secular trends and geographical variations in sex ratio at birth, albeit with mixed and often contradictory results. In addition, a multitude of environmental, social, economic, demographic and other factors has been proposed to influence the sex ratio at birth, thus complicating the interpretation of both secular trends and geographical variations. In this paper, the current state of knowledge on these issues is presented and critically assessed. Analyzing longer time series of sex ratio at birth with possible cycles and random components is given priority over establishing simple linear trends in the data. In analyzing the geographical variation in the sex ratio at birth, two different levels of analysis are distinguished (global and local), and two different sets of factors affecting the sex ratio at birth are proposed accordingly. Some key guidelines and future research directions are also proposed.
authors.affiliation: Department of Sociology, Centre for Croatian Studies, University of Zagreb, Borongajska cesta 83d, 10000 Zagreb, Croatia. Electronic address: dpavic@hrstud.hr.
authors.forename: Dario
authors.initials: D
authors.lastname: Pavic
mesh_terms: D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D036801:Parturition; D012621:Seasons; D012744:Sex Ratio
keywords: Geographical variation; Latitude; Secular trend; Sex ratio at birth; Time series