I guess its better for the third world to keep on having 8+ kids and immigrating here until our culture is extinct. Then at least we can pass into oblivion with a clear conscience. 1000 years from now people can read about those strange pale skinned people who built all the cities and invented strange technology then went extinct as they didnt have kids and their cities were occupied by hordes of people from the third world. Maybe we'll be kind of like Atlanteans.
God forbid we ask the third world to actually have a supportable number of children, heck if they have too many kids we can just have less ourselves then support theirs. Itll all even out in the end right.