A mature egg is reliably protected by a membrane, which is impossible for even a strong sperm to break through; the efforts of hundreds of “comrades-in-arms” are required, secreting enzymes to destroy the protection. If there is little strong genetic material, fertilization will require insemination with sperm prepared to penetrate the egg.
One sperm reaches the nucleus, after which the protective shell goes into high protection mode and does not allow male cells inside. Nuclear fusion occurs, forming a zygote containing 46 chromosomes with the genotype of a man and a woman. The fragmentation and formation of the embryo occurs after 25-30 hours.
The “losing” sperm do not die immediately, but continue to secrete chemical enzymes for a certain time. There is an assumption that in this way they provide a comfortable environment in the oviduct, so that it is easier for the fertilized egg to move into the uterine cavity. During insemination, a similar favorable situation is created with the help of medication.