I am not domiciled in a population declining nation, but by information , i am qualified to comment as demanded.
The problem as being witnessed by most Earopean nations is much more recalcitrant than they know , thus their aproach toward mitigating it s bound to fail woefully.
Psychological and Social reorientation is at the root of the problem. It is not a direct medical malady .
For centuries, the Western nation has championed the quest to consign NATURE and foundational truth to the dustbin of liberalism and "scientific progress" away from whatever that has been, to the extent that natural procreation is seen as old fashioned or sheer stupidity. New , hitherto abomoninable lexicons like Homosexuality , Bestiality etc has crept surreptiously into the social psyche , thus dousing the NATURAL instinct for procreation , low libido , errectile disfunction etc.
The remedy lies therefore , not in medication and persuation , financial inducement , but in retuning to NATURE !!
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