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 takes embryo 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 provides the potential to find cures and eliminate diseases. The dream of some researchers is to create a utopian world of good health. Others question whether it is right to "Play God" in an attempt to cure the disabilities and diseases of this world.

    Some of the great hopes for cloning include the ability to perform transplants， whenever they are needed， using cloned organs. For example， people with lung cancer may simply have their lungs replaced with healthy ones. Scientists also look forward to the day when people in wheelchairs can walk again， and illnesses such as Alzheimer's and Parkinson's Disease can be prevented.

    Many people fear the effects cloning could have on our society. They imagine masses of identical people， and the production of "perfect" humans for warfare or slave labor. We might even see headless human bodies being stored at hospitals for their "spare parts." With such thought-provoking possibilities for the 21st century， human cloning will no doubt continue to receive widespread attention and scrutiny.

    克隆一个你？

    挽救生命一直是科学研究的一项重要使命。如今，科学研究，其实是整个社会，正面临着一个新的困境：是否要设法通过克隆人类来挽救更多的生命。

    克隆实验开始于20世纪50年代，对象为青蛙和蟾蜍。直到1997年，科学家才成功地克隆了哺乳类动物，即世界闻名的“多莉羊”。克隆技术从那时起得到了持续的进展，今天已有了克隆老鼠、克隆鲑鱼和克隆牛。

    一些科学家想用克隆动物的方法，来为人类制造人类使用的皮肤、器官与其它的身体构造。其方法之一是从脑内或血液中提取成熟细胞，把它们培养成新组织。另外一种较为复杂的技术，则是把胚胎细胞培养成各式各样的细胞种类及组织。正是这个有计划的使用人类胚胎引起了争议与批评。

    克隆人类细胞有可能会找到治愈疾病的疗法并消灭疾病。一些研究人员的梦想是建立一个健康的乌托邦世界。其他研究人员则质疑人类企图治疗世上的伤残和疾病去扮演上帝的角色是否正确。

    人们对克隆的一些伟大希望包括在需要进行移植手术时，人们能使用克隆器官。例如：肺癌患者可能仅需换个健康的肺。科学家也期待着有一天，长期坐轮椅的人能再站起来，老年痴呆症及帕金森氏症等疾病也都能事先预防。

    许多人担心克隆对社会带来影响。他们想像可能会出现一大群长得一模一样的人，和应战争或苦役需要而制造出的“完美”人类。我们甚至可能看到存放在医院中作备用的无头的人体。在21世纪具有如此能激发思考的种种可能性的情况下，克隆人类毫无疑问会继续受到广泛的关注及审视。