I searched for a source to credibly defend that statement and have found none. I'm open to being shown otherwise. Some studies will bin people by BMI or some m

I searched for a source to credibly defend that statement and have found none. I'm open to being shown otherwise. Some studies will bin people by BMI or some metric but fail to do any analysis on whether people aren't fatter within the bins. E.g. if the bell curve shifts right, the average weight of people within the slimmest band will still be heavier than before; even if the maximum BMI/weight is still capped at the same upper bound. And the deltas on sperm counts within healthy weight ranges are very small in most studies to begin with. edit: searched in the past; not the few minutes since your comment*