How does fertilization restore the typical number of chromosomes in a human cell?

In humans, the typical number of chromosomes is restored through the process of fertilization, which unites two haploid gametes—the sperm and the egg.12

Prior to fertilization, these gametes undergo meiosis, a specialized form of cell division that reduces the chromosome count by half, resulting in cells that contain only one set of chromosomes. During fertilization, the male and female pronuclei meet within the egg's cytoplasm and lose their nuclear membranes. Each pronucleus contributes a complete single set of 23 chromosomes.132

The fusion of these two haploid sets creates a zygote with a full diploid number of 46 chromosomes. This reassociation is fundamental to sexual reproduction, as it restores the typical chromosome count and provides the genetic basis for biparental inheritance.123