@George-K said in Fascinating graphic of world fertility rates over time:
I can't recommend the book Klurrs pointed out - "Why We Sleep" highly enough.
(correlation ≠ causation warning here)
Coincident with the declining fertility rate is the declining amount of sleep that our society gets. Theres a definite correlation between sleep and sperm production. In the late 19th and early 20th centuries, the average amount of sleep was about 9 hours, now we're down to 7 or less.
Again, I don't know if that decrease in sperm counts correlates with the decrease in fertility, but the numbers do coincide.
“ men who report sleeping too little—or having poor-quality sleep—have a 29 percent lower sperm count than those obtaining a full and restful night of sleep, and the sperm themselves have more deformities”
And this:
“Take a group of lean, healthy young males in their mid-twenties and limit them to five hours of sleep for one week, as a research group did at the University of Chicago. Sample the hormone levels circulating in the blood of these tired participants and you will find a marked drop in testosterone relative to their own baseline levels of testosterone when fully rested. The size of the hormonal blunting effect is so large that it effectively “ages” a man by ten to fifteen years in terms of testosterone virility. ”
Well then I am sure I am locked and loaded.