I can recall only one article that was posted here which included that, but I came away thinking it was misleading. It binned weight categories(e.g. BMI ranges

I can recall only one article that was posted here which included that, but I came away thinking it was misleading. It binned weight categories(e.g. BMI ranges from X-Y) and showed that over time, people were falling into heavier categories, and that sperm outcomes were getting worse in every category (heavily in the obese, less so in the normal weight range). But if you eyeballed the curve it felt very likely that the distribution of individuals was just shifting the the heavier end within each category. E.g. if a healthy BMI is 18-25, and you look at the the average outcome for that group over time... if the whole population gets fatter then the mean value in the 18-25 group could shift from 20 to 22. So... take it as you will. Sorry for no source here either.