This article on The Guardian is like science fiction:
Sperm counts among men have more than halved in the last 40 years, research suggests, although the drivers behind the decline remain unclear.
The latest findings reveal that between 1973 and 2011, the concentration of sperm in the ejaculate of men in western countries has fallen by an average of 1.4% a year, leading to an overall drop of just over 52%
One other thing:
“If you are a guy with a low sperm count and you try for a baby when you are 21, you are probably not going to notice you’ve got a problem,” Pacey said. “But if you are trying with your partner when she is 35 then that’s when the heartache comes, because by then you have got low sperm count, you’ve got an older partner and you haven’t got a lot of time to try and fix it medically.”
Men should be considering that their body clock is ticking too ?
Sperm counts among western men have halved in last 40 years – study | Life and style | The Guardian : https://www.theguardian.com/lifeandstyle/2017/jul/25/sperm-counts-among-western-men-have-halved-in-last-40-years-study