"The rate at which human sperm counts are decreasing has more than doubled since the turn of the century, and the mean level has dropped below a threshold that makes conception significantly more difficult.

These findings are part of a new peer-reviewed study published today in the Human Reproduction Update journal that includes data from 53 countries and is the first meta-analysis to check levels in Central America, South America and Asia."

https://www.theguardian.com/science/2022/nov/15/global-human-sperm-count-decrease-doubled