There’s a lot to like about sperm. They’re driven, goal-oriented, and hey, they’re responsible for half of your genetic material.

That’s why it’s so disconcerting that these little dudes are dying off in droves. The total male sperm count has decreased by about half since the 1950s, according to a large study that came out in the early ’90s, which showed sperm counts had decreased from 113 million sperm per mL to 66 million sperm per mL over the course of 52 years. Though that study was critiqued, an analysis from a decade later reached similar conclusions, and the World Health Organization even lowered the numbers for what’s considered a “normal” sperm count in 2010, from 20 million per mL to 15 million sperm per mL.