The talk about large families misses the bigger picture.
The world population doubles every 50 years. Today there are 7 billion. What will we do in 100 years when the population is 28 billion and human technology is still stuck at burning things for energy? (With most oil gone.)
What are we going to do in 250 years when there are 224 billion? We will not have to wait until then to see unprecedented catastrophes where billions die.