Recent Examples on the WebBirth rates of identical twins, or monozygotic twins, where one egg is fertilized but splits into two eggs, remained the same at four identical births per 1,000 births, Live Science reports. Elizabeth Gamillo, Smithsonian Magazine, 16 Mar. 2021 Grown from the same, single fertilized egg, monozygotic twins have nearly identical genomes. Nadia Drake, WIRED, 4 Dec. 2014