and the embryo must be protected under the same ethical view as a more developed human being. History 1964: Lewis Kleinsmith and G. Barry Pierce Jr. isolated a single type of cell from a teratocarcinoma, a tumor now known from a germ cell. These cells were isolated from the teratocarcinoma replicated and grew in cell culture as a stem cell and are now known as embryonal carcinoma (EC) cells. Although similarities in morphology and differentiating potential (pluripotency) led to the use of EC cells as the in vitro model for early mouse development, EC cells harbor genetic mutations and often abnormal karyotypes that accumulated during the development of the teratocarcinoma. These genetic aberrations further emphasized the need to be able to culture pluripotent cells directly from the inner cell mass. 1981: Embryonic stem cells (ES cells) were independently first derived from a mouse embryos by two groups. Martin Evans and Matthew Kaufman from the Department of Genetics, University of Cambridge published first in July, revealing a new technique for culturing the mouse embryos in the uterus to allow for an increase in cell number, allowing for the derivation of ES cell from these embryos. Gail R. Martin, from the Department of Anatomy, University of California, San Francisco, published her paper in December and coined the term "Embryonic Stem Cell". She showed that embryos could be cultured in vitro and that ES cells could be derived from these embryos. 1989: Mario R. Cappechi, Martin J. Evans, and Oliver Smithies publish their research that details their isolation and genetic modifications of embryonic stem cells, creating the first "knockout mice". In creating knockout mice, this publication provided scientists with an entirely new way to study disease. 1996: Dolly, was the first mammal cloned from an adult cell by the Roslin Institute of the University of Edinburgh. This experiment instituted the proposition that specialized adult cells obtain the genetic makeup to perform a specific task; which established a basis for further research within a variety of cloning techniques. The Dolly experiment was performed by obtaining the mammalian udder cells from a sheep (Dolly) and differentiating these cells until division was concluded. An egg cell was then procured from a different sheep host and the nucleus was removed. An udder cell was placed next to the egg cell and connected by electricity causing this cell to share DNA. This egg cell differentiated into an embryo