Scientists Caught Sperm Ignoring a Major Physical Law - ScienceAlert

Smoke emanates from smokestacks at the Phillips 66 Bayway Refinery in Linden, New Jersey, on March 18, 2026. Air quality is linked to a wide range of health issues including respiratory problems, cardiovascular complications, and cancer, and that list of concerns only continues to grow. According to researchers presenting this week at the 42nd Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE), common pollutants may be fundamentally disrupting human sperm genetics—and these alterations may affect far more than male fertility.

Tails take up most of the real estate on a sperm cell. They may have tiny bodies, but fruit flies produce giant sperm. Adult male Drosophila melanogaster fruit flies are about two millimeters long (roughly the size of a sesame seed) and their sperm can be just as long, with the sperm tails taking up most of that space.