Gynecology Sexual anatomy

Zygote Wikipedia

A zygote (Greek language|Greek: ζυγωτόν) is a cell (biology)|cell that is the result of fertilization. That is, two haploid cells—usually (but not always) an ovum from a female and a sperm cell from a male—merge into a single diploid cell called the zygote (or zygocyte).

Animal zygotes undergo mitosis|mitotic cell divisions to become an embryo. Other organisms may undergo meiosis|meiotic cell division at this time (for more information refer to biological life cycles).

Twins and multiple births can be monozygotic (identical) or dizygotic (fraternal).