There's ample sperm count data over long time periods.

It would seem that a few thousands guy study ought to detect any sudden decline.

In Sweden it shouldn't take much to determine if there is an issue. Indeed, it should be showing up worldwide.

Are sperm reports being made to VAERS?

Counts have been steadily falling for years. (Jocky shorts??)

I believe the economy and future expectations are the primary drivers of having babies (silly religions aside).