If someone were paranoid it would seem pretty doomer. At worst you would expect birthrates to be halved over these years. But this is far from the case

Once sperm counts are above 40-50 million/ml, more doesn’t necessarily mean a higher chance of conception. However, once you drop below that amount, the probability of conception starts dropping off rapidly as sperm counts fall. The implications of this being that there shouldn’t be any noticeable trends in birthrate tied to sperm counts for now. Since the concentration is falling at an accelerated pace, this may soon have a noticeable impact on society.

There has been some research into potential causes, and I personally believe that it’s due to “endocrine disrupters” such as phthalates, PCBs, PFAS, BPA, BPS, and others. Since humans stand at the top of the food pyramid, all of these chemicals are accumulating within us. I don’t think there’s any escaping this; this is likely one of the possible Great Filters.