Cloning in biology is the process of producing populations of genetically-identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments, cells, or organisms. Embryo splitting is used as a strategy to increase the number of transferrable embryos, thus to increase pregnancy rate after embryo transfer. The first successful embryo splitting was in 1978, when Dr. Steen Willadsen, an embryologist in Windermere, Fla., divided sheep embryos in two.