Sperm have always been a precious commodity, given the critical role they play in generating new life. Even a relatively small change in the typical sperm count has a substantial impact on the percentage of men who will be classified as infertile or subfertile. It’s not just about sperm count, however; certain qualities, including movement patterns, are also essential for them to swim upstream to meet the egg of their dreams.

The study of sperm began, unsurprisingly, in a fairly bizarre fashion. In 1677, Antoni van Leeuwenhoek, a Dutch tradesman and self-taught scientist who was fascinated with microscopes, collected his semen and examined it under a microscope, where he saw millions of tiny, wriggling shapes called animalcules (little animals) swimming in the fluid. He believed that each sperm contained a miniature, preformed human being that would unfurl and develop inside the mother after being nourished by the female egg.