悦读教材高二英语•外研版•选修6（下）：Module 5 Cloning

Module 5 Cloning Is Cloning the Future? Saving lives has always been an important mission of science. Now science, and indeed all society, is facing a new dilemma: whether or not to try and save more lives through human cloning. The first cloning experiments in the 1950s involved frogs and toads. It was not until 1997 that scientists successfully cloned the first mammal, the now world-famous sheep known as Dolly. Cloning techniques have continued to improve since then, and today there are cloned mice, salmon, and cattle. Some scientists want to apply the methods used in cloning animals to produce skin, organs, and other body parts for humans. One of these methods involves taking adult cells from the brain or blood and growing them into new tissues. Another, more complex, technique takesembryo cells and develops them into a wide variety of cell types and tissues. It is this planned use of human embryos that has resulted in controversy and criticism. The cloning of human cells provide