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.
Mid-twentieth century baby boom
Economist and demographer Richard Easterlin in his "Twentieth Century American Population Growth" (2000), explains the growth pattern of American population in the 20th century by examining the fertility rate fluctuations and the decreasing mortality rate. Easterlin attempts to prove the cause of the baby boom and baby bust by the "relative income" theory, despite the various other theories that these events have been attributed to. The "relative income" theory suggests that couples choose to have children based on a couple's ratio of potential earning power and the desire to obtain material objects. This ratio depends on the economic stability of the country and how people are raised to value material objects. The "relative income" theory explains the baby boom by suggesting that the late 1940s and the 1950s brought low desires to have material objects, because of the Great Depression and World War II, as well as plentiful job opportunities (being a post-war period). These two factors gave rise to a high relative income, which encouraged high fertility. Following this period, the next generation had a greater desire for material objects, however an economic slowdown in the United States made jobs harder to acquire. This resulted in lower fertility rates causing the Baby Bust.