.

It's mostly religious purposes and old traditions mixed with the lack of access to condoms. Having big families and procreating is the best thing ever to them

my country is lower than I expected.

Less education.

/endthread

Less educated people

this

sex

Less education so less career driven people + people being extremely religious.

They simply don't use birth control which takes us back to their poverty

Wow, the one child policy is really affecting China's birth rate of this generation.

Isnt it so some of their children can be lucky and be rich and powerful?
An example of that is the Jackson family with Michael and Janet being pretty much the youngest of that huge family

Boredom

This. Also in many poor countries, abortions are illegal. And poorer countries are often more religious due to hope... and religions generally oppose abortions/contraception

I'd also say high (child) mortality rate and the fact that people need their children to care for them in the future affect the birth rate

Lack of contraceptives as mentioned, and because of the health conditions in many places. The more kids you have, the more likely a good bunch can survive and keep the line going.
An issue there though would be the amount of resources available in order for that to succeed.

Other than the reasons listed here already - children are essentially, assets. The more people working for & within the family, the better off they can be.