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Scientists have used cloning technology to transform human skin cells into embryonic stem cells, an experiment that may revive the controversy over human cloning. 科学家利用克隆技术将人体皮肤细胞转化为胚胎干细胞。这一实验可能再次引发有关克隆人的争论。 The researchers stopped well short of creating a human clone. But they showed, for the first time, that it is possible to create cloned embryonic stem cells that are genetically identical to the person from whom they are derived. 研究人员的成果距创造出克隆人还很遥远，但他们首次表明，创造出同人类基因完全相同的克隆胚胎干细胞是可能的。这些胚胎干细胞就来自人类。 These stem cells can go on to differentiate into heart, nerve, muscle, bone and all the other tissue types that make up a human body. 这些干细胞可以分化成心脏、神经、肌肉、骨骼和其它所有组成人体的组织型。 Since the birth of Dolly the sheep in 1996, researchers have cloned about 20 different species, including rabbits, goats, cows and cats. Yet they so far have been unable to create biologically identical copies of any monkey or primate, including humans, possibly because their reproductive biology is more complicated. 自1996年克隆绵羊多莉(Dolly)诞生以来，研究人员已经克隆出大约20个不同物种，包括兔子、山羊、奶牛和猫。然而研究人员至今无法创造出在生物性上完全相同的猴子或灵长类动物（包括人类）的克隆体，原因可能在于这些生物的生殖生物学更复杂。 | 
