Abstract
This review discusses definitions of parthenogenesis, haploid, diploid and polyploid parthenogenesis; parthenogenesis and sex determination; some examples of parthenogensis in invertebrates such as thelytoky in insects and other invertebrates; cyclical haploid parthenogenesis [arrhenotoky] in Hymenoptera; parthenogenesis in vertebrates such as gynogenesis in fish and amphibia; other types of parthenogenesis in fish, amphibia, reptiles, birds and mammals [spontaneous and induced]; and the significance of fertilization.