Might be hard to believe but :
1) They don't have the same access to contraception that we have in Occident.
2) More children die so they give birth to more children.
3) African countries generally do not give pension to seniors. More children who can work once they grow up (or not) = more people to take care of your old ass.
One of the rare social cause I want to work for are is overpopulation, it's bothering me that poor countries citizen do give birth to a whole lot of children but at least I can understand why they do it. It has always been like this. Don't want to be mean or anything by the and it's the internet, so answer me as you want or ignore me, I'm not expecting anything from this.