The researchers used a statistical model to analyse whether son preference increases mortality rates for girls through family-building processes. In the Republic of Korea, girls' mortality rate is lower than boys, but still higher than expected. In Egypt, girls who have older surviving brothers and sisters have higher mortality rates. In Bangladesh, it is girls with older brothers who experience particularly high mortality. When son preference is present, girls are likely to suffer as a result of family-building processes.
Girls are more likely to be followed by a younger sibling after a short interval.
In all three countries, children who have a sibling born within 24 months have higher risks of mortality. Where mortality levels are high, such as in Egypt and Bangladesh, family building explains only a small part of excess female child mortality. In the Republic of Korea, where mortality levels are lower and socio-economic conditions are good, the family building process explains much of the higher than expected level of female mortality. Where parents have insufficient resources to provide quality care to all their children, they may favour some children over others, and it is often girls who lose out. Look at the Population Council website for research on population and social policy.