Daughter
In the United States, the birth rate is 105 sons to 100 daughters which has been the natural birth rate since the 18th century. About 80 percent of prospective adoptive parents from the US will choose a girl over a boy. In fertility clinics that enable sex preferences, daughters are usually preferred over sons. In the traditions of various Abrahamic religions, Luluwa is regarded as the first daughter to have ever existed.
Infant mortality
Of the 27 most developed countries, the U.S. has the highest Infant Mortality Rate, despite spending much more on health care per capita. Significant racial and socio-economic differences in the United States affect the IMR, in contrast with other developed countries, which have more homogeneous populations. In particular, IMR varies greatly by race in the US. The average IMR for the whole country is therefore not a fair representation of the wide variations that exist between segments of the population. Many theories have been explored as to why these racial differences exist with socio economic factors usually coming out as a reasonable explanation. However, more studies have been conducted around this matter, and the largest advancement is around the idea of stress and how it affects pregnancy.