Earlier quoted context omitted.
It's a Catch 22. Are they poor because they have too many children or are they having too many children beacsue they are poor?
Are you implying that having many children might lead to better outcome financially?
In some traditional areas, it probably depends on the gender of your children too.
Additionally, there are 'soft' benefits, like older children providing child care or adult children taking care of their parents or in-laws.