…said that his research had shown that men with a higher body mass index (BMI) had lower volumes of seminal fluid and a higher proportion of abnormal sperm. …. “Other studies have suggested an association between male obesity and increased DNA damage in the sperm, which can be associated with reduced fertility as well,” said Dr. Shayeb.
Men who eat an average ofhalf a serving of soy food a day[my emphasis] have lower concentrations of sperm than men who do not eat soy foods, according to research published online in Europe’s leading reproductive medicine journal, Human Reproduction, today (Thursday 24 July). The association was particularly marked in men who were overweight or obese, the study found.
Men who cycle a lot can also experience changes to their sperm function, because of the excessive heat generated in the pelvic area. No general link between cycling and male infertility has been established, but it is still recognised as a possible side effect and has been noted in a number of male cyclists.