Life perpetuates through successful fertilization. We study membrane receptors, ion channels, and their downstream signaling molecules that regulate sperm motility and fertility in mammals. In particular, we study the primary calcium channel “CatSper” and its accessory subunits. Strong evolutionary pressure on reproduction have endowed sperm with highly evolved and specialized calcium signaling complexes. A long-term goal is to elucidate the unique molecular and structural adaptations in the ion channels complex that mediate successful fertilization as well as other critical, physiological events in mammalian reproduction. To this end, we use a variety of approaches including mouse genetics, biochemical studies, dynamic optical imaging of live cells, and cutting-edge super-resolution microscopy. Our research has clinical implications in the treatment of human infertility as well as contraception, and expands our understanding of calcium signaling.