Embryo Transfer is an ever changing and expanding field. The first calf produced experimentally was in 1951, but it took until the 1970's for the first calf to be commercially produced (in England). The commercial embryo transfer industry in North America developed in the early 1970's with the introduction of exotic European breeds of cattle. Embryo transfer is basically used to exploit the genetics of the female in the same way that frozen semen is used to exploit the genetics of the male. As ET technology developed and improved, embryo transplant became more commonplace and affordable. It was used for genetic improvement rather than for increasing numbers of a particular breed or phenotype. Today it is the main method of moving genetic matings around the world.