It's difficult to talk about because it's not politically correct (or politically advantageous) to talk about the root cause issues. So you get bean-counters selling dystopian nightmares.

Generally speaking, high birth rates correlate with poverty. Improve standards of living, particularly for woman and disconnect access to medical & family planning resources from religion and birthrates decline. If you don't think that 50% of your kids will die before reaching adulthood, you don't have 12 children.

The 1 million pound gorilla is our collective failure to look past our tribal/national boundaries.