Read the source "Human development begins after the union of male and female gametes or germ cells during a process known as fertilization (conception)." "Fer

Read the source "Human development begins after the union of male and female gametes or germ cells during a process known as fertilization (conception)." "Fertilization is a sequence of events that begins with the contact of a sperm (spermatozoon) with a secondary oocyte (ovum) and ends with the fusion of their pronuclei (the haploid nuclei of the sperm and ovum) and the mingling of their chromosomes to form a new cell. This fertilized ovum, known as a zygote, is a large diploid cell that is the beginning, or primordium, of a human being." Moore, Keith L. Essentials of Human Embryology.