Abstract: Mammalian fertilization is the process by which highly differentiated male and female gametes combine to form a syncytium that initiates the development of a new living individual. During the process of sperm-egg cell fusion, the sperm-delivered genetic material and functional molecules would trigger a series of biological events that would activate the egg arrested in the meiotic prophase through inducing an acute increase in cytosolic free Ca²⁺ concentrations to give rise to calcium oscillations. The release of cortical granules is the first sign of egg activation. This paper reviews the identification, structure and action mechanisms of sperm PLCζ and its similar molecules and discusses the reproductive disorders in humans and mammals caused by related sperm defects, as well as the corresponding artificial egg activation methods, with a view to providing references to enhance human reproductive health and improve the efficiency of animal reproduction.