我们希望子女像我们自己。即使是采用捐赠卵子或捐赠精子的夫妇也要查找精子捐献人名录，以发现与自己相像的人。若干年前，琳达· 帕斯坦写的一首题为《致离家的女儿》的诗曾出现在纽约地铁的墙上，诗中写道：
难道是我自己的形象
映在你的脸上
使我如此爱恋？
我俯视着安睡的你
就像那喀索斯俯视着
他那一潭清水，
随时准备跳下去――
如有必要
为你沉溺
然而，如果我们如此爱恋在子女身上映现出来的自我，那为什么我们当中有这么多人，一想到将目睹与我们完全一样的基因复制品、比自己年轻许多的双胞胎降生的时候，就会感到如此惊恐？难道大自然通过基因的任意组合将我们造就是一回事，而由我们自己实施全面控制，摈弃一切随意的念头，通过基因组合造就一个与我们相似但更为完美的孩子则又是另外一回事？当男女一起生育孩子时，孩子往往是两个人基因的不可预料的组合。显然，一个老笑话表明我们已经认识到了这一点。这个笑话说的是一位漂亮但蠢笨的女人向一个丑陋但才华横溢的男人建议两人一起生一个孩子。想一想吧，那女人说，孩子拥有我的容貌、你的大脑那将会多么出色。啊，那男人说，可要是孩子继承了我的容貌你的大脑呢？
9 Cloning brings us face-to-face with what it means to be human and makes us confront both the privileges and limitations of life itself. It also forces us to question the powers of science. Is there, in fact, knowledge that we do not want? Are there paths we would rather not pursue?
克隆技术使我们直接面对做人的意义这个问题，使我们直接面对生命本身的特权与限制。克隆技术也迫使我们对科学的力量提出质疑。是不是有些知识我们真的不要去获取？有一些路我们宁愿不去探寻？
10 The time is long past when we can speak of the purity of science, divorced from its consequences. If any needed reminding that the innocence of scientists was lost long ago, they need only recall the comments of J. Robert Oppenheimer, the genius who was a father of the atomic bomb and who was transformed in the process from a supremely confident man, ready to follow his scientific curiosity, to a humbled and troubled soul, wondering what science had let loose.
我们奢谈科学的纯洁性，将科学与其后果分离的时代早已过去。如果有谁还需要提醒，科学家的纯真早已丧失，他们只要回想一下J·罗伯特·奥本海默的话。奥本海默是一位天才，他是原子弹的缔造者之一。他在追求科学的过程中，从一个极其自信、随时准备跟着科学好奇心走的人，逐渐变成了一个谦恭困惑的人，他不知道科学放出了什么妖魔。
11 Before the bomb was made, Oppenheimer said, "When you see something that is technically sweet you go ahead and do it." After the bomb was dropped on Hiroshima and Nagasaki, in a chilling speech delivered in 1947, he said: "The physicists have known sin; and this is a knowledge which they cannot lose."
在原子弹造出之前，奥本海默说：“当你看到某个技术完美的东西时，你就毫不犹豫地去实现它。”原子弹投在广岛、长崎之后，他在1947年发表的一则令人毛骨悚然的演说中指出：“物理学家们已经尝到过罪孽的滋味，这种滋味他们无法忘记。”
12 As with the atom bomb, cloning is complex, multi-layered in its threats and its promises. It offers the possibility of real scientific advances that can improve our lives and save them. In medicine, scientists dream of using cloning to reprogram cells so we can make our own body parts for transplantation. Suppose, for example, you needed a bone marrow transplant. Some deadly forms of leukemia can be cured completely if doctors destroy your own marrow and replace it with healthy marrow from someone else. But the marrow must be a close genetic match to your own. If not, it will lash out at you and kill you. Bone marrow is the source of the white blood cells of the immune system. If you have someone else's marrow, you'll make their white blood cells. And if those cells think you are different from them, they will attack.
如同原子弹一样，克隆技术带来的威胁与希望是复杂的、 多层面的。它提供了改善生活、拯救生命的真正科学进步的可能性。在医学上，科学家梦想着运用克隆技术改编细胞的编码指令程序，这样我们就可以制造出我们自己身体的某些部分进行移植。比如说，假定你需要进行骨髓移植。如果医生摧毁你自身的骨髓，用他人的健康骨髓来取代，某些致命的白血病就能得到彻底的医治。但骨髓的属型必须与你自己的相匹配。不然的话，移植的骨髓就会向你发起进攻，置你于死地。骨髓是免疫系统的白细胞的来源。如果你获得别人的骨髓，你就会造出别人的白细胞。如果这些白细胞认定你与它们不同，它们就会发起进攻。
13 But suppose, instead, that scientists could take one of your cells -- any cell -- and merge it with a human egg. The egg would start to divide, to develop, but it would not be permitted to divide more than a few times. Instead, technicians would bathe it in proteins that direct primitive cells, embryo cells, to become marrow cells. What started out to be a clone of you could grow into a batch of your marrow -- the perfect match.
不过，可以有别的办法。假定科学家能够用你自身的某个细胞――任何一个细胞――将它与人的卵细胞融合。卵细胞开始分裂，生长，但你可以控制它，只让它分裂若干次。技术人员将它置于蛋白质当中，指令原始细胞，即胚胎细胞，长成骨髓细胞。开始时本可以克隆你的东西却可以长成一批你的骨髓――与你完美相配的骨髓。
14 More difficult, but not inconceivable, would be to grow solid organs, like kidneys or livers, in the same way.
更为困难，但并非不可思议的，是以同样的方法长成完整的器官，如肾脏或肝脏。
15 Another possibility is to create animals whose organs are perfect genetic matches for humans. If you need a liver, a kidney, or even a heart, you might be able to get one from a specially designed pig clone.
另一种可能性是生成器官与人类基因完全吻合的动物。如果你需要肝脏，肾脏，甚至心脏，你或许能从一头特别设计的克隆猪身上获得。
16 The possibilities are limitless, scientists say, and so, some argue, we should stop focusing on our hypothetical fears and think about the benefits that cloning could bring.
科学家称克隆技术蕴藏着无穷的可能性，因此，有人争辩说，我们不应该喋喋不休地谈论种种假设的恐惧，而去想一想克隆技术能够带来的裨益。
