Fertilization is the first stage of embryogenesis, as a result of which the union of male and female sex cells leads to the appearance of a diploid ovum, the zygote.
Perhaps you will be interested to know how this egg turns into a blastomer, and the blastomer into a trophoblast and an embryoblast, not necessarily. And most likely, you are not interested in what morphological changes occur in the embryonic mesoderm during gastrulation ...
But those who are still unsuccessfully trying to become a mother, as well as those who want to avoid unwanted pregnancy, the information in this section will be useful. Fertilization occurs only in favorable conditions.