This Sunday Times article strongly suggests that obesity is linked to male infertility because the protein messengers which help to code for Sperm production are chemically disrupted by the way we live and eat.
These subtle but persistent influences probably have effects which can be inherited, and although we cannot point to a measurable genetic mutation (yet), this may be a discovery for the future.
Sunday Times, February 16th 2020: Dad’s Bad Diet Damages His Sperm and His Kids
‘Men with poor diets risk producing damaged sperm that puts their children at risk of obesity and diabetes, writes Jonathan Leake.
Research suggests that a diet low in nutrients damages RNA molecules, which help sperm swim towards an egg, fertilise it and initiate the formation of a healthy foetus…..’