Synthetic endocrine disrupting chemicals (EDCs) interfere with the endocrine system; EDCs that are omnipresent in food, air, textiles, pharmaceuticals, household products, and personal-care products mimic the action of natural hormones and affect their production or metabolism. EDCs have been implicated in adverse trends in human reproduction, including widespread infertility and increasing demand for assisted reproduction. However, it has been difficult to prove or refute the hypothesis that EDCs account for the decreasing reproductive success.

We studied by Ca²⁺ fluorimetry, patch-clamp recordings, and motility analysis the action of about 100 ubiquitous EDCs on human sperm. We find that structurally diverse EDCs, at physiologically relevant concentrations, directly activate the sperm-specific CatSper Ca²⁺ channel and, thereby, evoke an increase of intracellular Ca²⁺ ([Ca²⁺]_i), a motility response, and acrosomal exocytosis. EDCs compete with progesterone and prostaglandins for CatSper activation and desensitize sperm for these physiological ligands. Moreover, in complex low-dose mixtures reflecting physiological exposure levels, EDCs cooperate to elevate [Ca²⁺]_i in sperm.

We conclude that EDCs directly interfere with various sperm functions and, thereby, might impair human fertilization.