There are a number of studies. I wouldn't call that a lot of evidence, because they don't agree on the results. And, because the methodology changes over time,

There are a number of studies. I wouldn't call that a lot of evidence, because they don't agree on the results. And, because the methodology changes over time, it's probably just not possible to say that there is evidence of change between pre and post-90s papers. https://www.nature.com/articles/s41585-022-00626-w.epdf https://www.nature.com/articles/s41585-022-00626-w.epdf https://www.scientificamerican.com/article/are-sperm-counts-really-declining/ https://www.scientificamerican.com/article/are-sperm-counts-... There need to be more studies of higher quality to actually establish what is happening. It's really not clear right now that anything is happening, and, if it is, if it's even a problem.