Does it not strike you as strange though that so many different nations / cultures are all seeing the same downward trend at the same time? There is something about it that feels like a biological imperative.
We have better things to do than hump like rabbits? We don’t need kids to work the farm, or to provide net positive muscle power input to the economy. We have machines for that.
>higher rates than before (welcome hookup culture)
Got any source to back that up? All surveys I have seen point to younger generations having less sex, fewer relationships, and even just drinking less than their ancestors. Remember, the boomers were the "free love" hippies and then STDs became a serious concern, and we decided we should warn kids about consequences of sex.