To be sure, I’m not an expert on the topic.
Declines in male fertility I think are regarded as real, though I haven’t examined the primary sources.
Regarding female fertility, this report from Norway outlines the trend that I vaguely thought was representative of most of the developed world over the last 100 years.
Female fertility is trickier to measure, since female fertility and age are strongly correlated, and women have been having kids later, so it’s important (and likely tricky) to disentangle this confounder from the data.
Is meditation provably more effective than “forcing yourself to do nothing”?
Much like sleep is super important for good cognitive (and, of course, physical) functioning, it’s plausible that waking periods of not being stimulated (i.e. of boredom) are very useful for unlocking increased cognitive performance. Personally I’ve found that if I go a long time without allowing myself to be bored, e.g. by listening to podcasts or audiobooks whenever I’m in transition between activities, I’m less energetic, creative, sharp, etc.
The problem is that as a prescription “do nothing for 30 minutes” would be rejected as unappealing by most. So instead of “do nothing” it’s couched as “do this other thing” with a focus on breathing and so on. Does any of that stuff actually matter or does the benefit just come from doing nothing?