If you are to look specifically at the health angle (and it surprisingly even affects our mental health), we have suffered a double whammy of the change in diet

If you are to look specifically at the health angle (and it surprisingly even affects our mental health), we have suffered a double whammy of the change in diet plus the widespread use of antibiotics. It is becoming increasingly clear that our gut microbiome has a wide-ranging affect on many aspects of our health; and that the standard western diet is not good for a healthy gut microbiome and that taking antibiotics can have a detrimental affect on the gut microbiome as well. Our gut bacteria are not only responsible for digesting much of the foods we eat. They regulate our immune systems. They also create chemicals that pass into our blood steam, and even pass the blood brain barrier, affecting our behavior. There has been a severe decline in the health of our gut microbiome in recent generations. The extent this has had an impact on our lives is yet to be determined –– I suspect the rise of food allergy problems is at least one of the issues. There is also the possibility that this has been a major factor in the rise of autism (which is commonly accompanied by IBD), as well as the significant increase in IBD diseases. It certainly seems possible to me that sperm count could be affected by our body's digestion system, and the health of the gut microbiome that is so central to it.