Some scholars argue that strong socioeconomic factors such as the dowry system in India and the one child policy of China are responsible for prenatal sex selection. In a widely cited article,[21] Amartya Sen supported such views. Other researchers argue that an unbalanced sex ratio should not be automatically held as evidence of prenatal sex selection; Michel Garenne reports that many African nations have, over decades, witnessed birth sex ratios below 1.00, that is more girls are born than boys.[22] Angola, Botswana and Namibia have reported birth sex ratios between 0.94 and 0.99, which is quite different from the presumed "normal" sex ratio, meaning that significantly more girls have been born in such societies.[23]