Related to that last post--specifically to Mark Steyn's talk about modern Westerners' lack of confidence in our civilization and the Morse columnist's pointing out that Islamists believe in themselves enough to replace themselves--is this quote from Thomas Sowell:
"No society can survive in the long run without the allegiance of its people. Undermining a sense of the worthiness of a society undermines that allegiance -- and, without allegiance, there is no defense." (Thomas Sowell)
This is true. For the obvious reasons that people who continually downgrade everything their civilization has produced and stands for are unlikely to support it against attack, intellectual or otherwise, or to build it up by continuing and strengthening its traditions and accomplishments. But perhaps also they may be less likely to want to reproduce--if they sincerely believe their civilization is worthless, that is.
Don't get me wrong, I think selfishness and a desire to overplan and overcontrol every aspect our lives is behind most of the childlessness in our society (I say this as a childless woman), but I can see how thinking your whole civilization is without redeeming features could make you reluctant to reproduce. Animals caged in zoos often don't want to reproduce, even though you'd think, if nothing else, they'd welcome the change in routine that a spot of reproductive fun could bring; it may just be my fruitcakey side speaking, but I've always thought it might be because they sense they are not free animals and aren't really content with that that they are able to override the second or third most powerful urge any of us have. Why should a human that views its society and heritage as worthless be any different from the zoo animal that finds little to live for in its environment?