Demographics of the world
According to the CIA - The World Factbook, the country with the highest birth rate currently is Niger at 51.26 births per 1000 people. The country with the lowest birth rate is Japan at 7.64 births per 1000 people. Hong Kong, a Special Administrative Region of China, is at 7.42 births per 1000 people. As compared to the 1950s, birth rate was at 36 births per 1000 in the 1950s, birth rate has declined by 16 births per 1000 people. In July 2011, the U.S. National Institutes of Health announced that the adolescent birth rate continues to decline.
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.