The union of sperm and egg is not difficult, only the process is more complicated. There are four steps: sperm capacitation, acrosome reaction, zona pellucida reaction, and fertilized egg formation. 1. Sperm capacitation: when the sperm is ejaculated into the vagina, after 15 minutes to half an hour of liquefaction, the sperm leaves the semen and enters the cervix, uterine cavity and fallopian tubes of the woman, the glycoprotein on the surface of the acrosome of the sperm is broken down by the amylase enzyme in the secretions of the reproductive tract, so that the sperm has the ability to fertilize the egg, which is called sperm capacitation. 2. Acrosome reaction: when sperm and egg meet, the outer membrane of the acrosome of the sperm head and the top of the sperm cell membrane rupture to form a small hole, releasing acrosomal enzymes to dissolve the peripheral radial crown and zona pellucida of the egg, which is known as the acrosome reaction. 3. Zona pellucida reaction: the surface of the egg comes into contact with the head of the spermatozoon, and at the same time, the lysosomal enzymes released by the cortical granules in the egg can change the structure of the zona pellucida, preventing other spermatozoa from entering the zona pellucida. This process is called zona pellucida reaction. 4. Fertilized egg formation: The fusion of the nucleus of the oogonium and the nucleus of the spermatogonium results in the formation of a fertilized egg. After the sperm and egg have combined, a fertilized egg is formed and can successfully attach itself to the ovum, and conception begins. If you are planning to get pregnant, please abstain from smoking and alcohol and prepare for pregnancy under the guidance of your doctor.