Demographic Winter is the name of a documentary that my seminarian friend (Brian) sent me. He has watched the entire film, (which is totally secular), and expresses the need for societies to stop freaking out about the hype surrounding having "too many people in the world" and start having kids!
In order for our society (and world) to survive, demographers (and statistics) say we need to "replace" ourselves at a birth rate of 2.1, which makes sense - 2 children to replace the 2 parents that gave them life and .1 to factor in all sorts of other birth complications .... currently, most countries are at 1.something - - - -
There will soon be too many old people in the world for the lack of young people left in our world to support them.
What I find most interesting about the trailer that I have given you the link to, is that these secular demographers, state that the "in-tack male+female family unit" is the strongest and most successful way for our world to survive.
Check it out, and try to watch the entire film if you can.
Hooray for marriage and family life!