That birth rates vary from country to country, is a relatively new phenomenon. The reason why there are different birth rates is that the countries are in a different state of the so called 'demographic transition'. It usually has 4 stages which a country passes:
Stage 1: High birth and high Death Rate (all countries before industrial revolution)
Stage 2: High birth and falling death rate (some African countries)
Stage 3: falling Birth Rate and low death rate (most of the developing countries)
Stage 4: low birth rate and low death rate (developed countries)
The birth rates fall because there's no need for children as workers anymore. Countries in stage 1 and 2 are rural societies that demand child labor in the fields. The people have also to compensate the high Infant Mortality Rate. In stage 3 lesser and lesser people work in agriculture and children are no longer an economic benefit but a burden for the parents.
There's also much divergence in the birth rate in stage 4 countries. Most of the developed countries will go to the Stage 5 of the transition, with a death rate higher than the birth rate. Only two developed countries will not: USA and Israel. This has cultural reasons.
people have lots of babies because they can go out to work at a young age, and get the family money, and also they must like sexual intercourse
Decreasing the infant mortality rate will limit population growth in developing nations
"Infant mortality rates are high in India" "The infant mortality rate is 2 out of every 1000 live births"
Infant Mortality Rate; 1,000 born/43.61 deaths
The District of Columbia has the highest infant mortality in the United States.
higher birth rates, higher death rates, shorter life expectancies, and larger family sizes. These populations tend to have higher levels of poverty and less access to education and healthcare compared to populations that have experienced demographic transition.
The infant mortality rate of Iraq is 28 deaths out of 1000 live births.
the Infant Mortality Rate declined
The infant mortality rate in the UK is 2014 was 4.2 per 1000.
The infant mortality rate in Suriname in 2014 was 27.07 per 1,000.
The U.S is 33rd on the list for infant mortality.
the infant mortality rate for japan is 2.4 per 1000 people.
The infant mortality rate is 43 deaths per 1000 live births.