Women are the ones who have to sacrifice the most for children, so now that they have a choice, they don't do it nearly as much: some have none, others only have 1 or 2 and they've had enough. For replacement rate, every woman needs to have 2.1 kids on average, and not nearly enough women want to have 3+ kids to make up for all the women having fewer (which also includes infertile women don't forget).
And also with men and women being much more equal, men are expected to invest much more effort in child-rearing now, instead of just banging their wives and then letting them deal with the consequences while they do other stuff with their time. Well they don't want to deal with 6 kids either, and many don't want to deal with any.
It should be acceptable for any population to ebb and flow, as changes in internal and external forces occur. Deciding to import warm bodies because your economic ponzi appears to require it seems like short term thinking. It would be better if the ponzi itself was addressed and the population allowed to ebb for awhile.
People are easy to attract to your country when you really need them ... unless you've managed to make that country undesirable.
It may sound stupid but it was not obvious a hundred years ago. The wife is pregnant again, well, must be an act of god.
Try to imagine. There is no google search to find out how to make children. The closest library is far away and it's not that common to go to school and learn to read. That leaves you with the opinions of the family, the neighbors and the priest, who don't know much either and offer contradictory explanations.
I have to assume you're trolling, but to be charitable, here[0] is the Wikipedia article on the history of birth control. It starts in 1800 BC with ancient Egyptian writings describing the use of acacia and honey as a spermicide.
People knew where babies came from way before the internet.
I think you missed the GP's primary point. Just because someone in the entire world had the requisite knowledge might mean nothing at all to another someone a mere few hours of travel away, let alone on the other side of the world.
That's why written language was such a huge invention[1]. Then the printing press. Then the telegraph, radio, and telephone. Finally, the Internet. I'm sure I missed a few, but you get the idea.
[1] A moment of silence for the Libary at Alexandria, please
For example, here's an article on Samuel Pepys and a sexual manual from 1680 which quite clearly demonstrates that the nature of carnal knowledge was generally known at the time[0]. Along with death and mortal fear, sex and birth comprises one of the archetypal constants of the human experience. It's everywhere. It also happens to be knowledge that's necessary to continue the species, which humans have proven quite good at.
I guarantee that our parents knew how babby was formed, as did their parents, as did their parents, etc. Even our hominid ancestors before the formation of language understood it, because even animals understand it at an instinctive level.
[0]http://theappendix.net/posts/2013/06/this-misterie-of-fuckin...
The problem for something like contraception, which is the context here, is in understanding the details. Those details are sorely lacking in plays, songs, fairy tales, and old wives' tales.
> It also happens to be knowledge that's necessary to continue the species
No knowledge is actually necessary, as mere ignorant performance of the act is sufficient.
There is economics in the cultural change - as people get wealthier and government welfare becomes more reliable the forces behind maintaining and growing the family decreases. Wealthy people in the past still had many more kids than they do now though, so there's probably a bigger explanation.