9 things your guy is doing that are lowering his sperm count When you’re trying to get pregnant, it’s time for him to re-evaluate these sperm-count-lowering habits that are interfering with your chances of conceiving. We hate to hurt their egos, but modern men’s sperm are coming up short. According to a 2017 study by the Hebrew University of Jerusalem, sperm counts among Western men have dropped more than 50 percent in the past 40 years. While scientists can’t pinpoint an exact explanation, studies have shown that certain lifestyle factors play a large role in a man’s sperm count. The good news is that, most of the time, those levels aren’t permanent.