Lloyd and Mensch (2008), however, found that almost 30% of young women who left secondary schooling before completion in Chad and Nigeria cited early marriage as the main reason. The persistence of gender gaps in secondary education in Sub-Saharan Africa and Southern Asia, where early marriage rates remain high, indicates that discriminatory social institutions need to be addressed to enable girls to reap the full benefits of education (Field and Ambrus, 2008). This phenomenon - a particular problem in Southern Asia, China and parts of the Caucasus and Western Balkans - is rooted in social norms that favour sons over daughters because they represent lifelong economic support while daughters are economic burdens (UNFPA, 2007).