Imagine two people are listening to music.
想象一下有两个人在听音乐。
What are the odds that they are listening to the exact same playlist? Probably pretty low.
他们在听同样一个播放列表的几率有多大？很可能非常低。
After all, everyone has very different tastes in music.
毕竟每个人对音乐的喜好都不同。
Now, what are the odds that your body will need the exact same medical care and treatment as another person's body? Even lower.
那么，你的身体需要与另一个人完全相同的医学治疗和处理的几率又有多大呢？那就更低了。
As we go through our lives, each of us will have very different needs for our own healthcare.
在我们的一生当中，每个人在自己的医疗方面都有截然不同的需求。
Scientists and doctors are constantly researching ways to make medicine more personalized.
科学家和医生都在坚持不懈的寻找让医疗变得更有针对性的个性化方法。
One way they are doing this is by researching stem cells.
其中一个方法就是研究干细胞。
Stem cells are cells that are undifferentiated, meaning they do not have a specific job or function.
干细胞是未分化的细胞，也就是说它们还不具有某种特异作用或功能。
While skin cells protect your body, muscle cells contract,
表皮细胞可以保护我们的身体，肌细胞可以伸缩，
and nerve cells send signals, stem cells do not have any specific structures or functions.
神经细胞可以传递信号，而干细胞没有任何特异性的结构或者功能。
Stem cells do have the potential to become all other kinds of cells in your body.
但是干细胞具有成为体内所有其他细胞的潜力。
Your body uses stem cells to replace worn-out cells when they die.
我们的身体利用干细胞来取代无法正常发挥功能的死细胞。
For example, you completely replace the lining of your intestines every four days.
比方说，人体每4天就会更新一次肠壁细胞。
Stem cells beneath the lining of your intestines replace these cells as they wear out.
肠壁下部的干细胞会取代这些老化的细胞。
Scientists hope that stem cells could be used to create a very special kind of personalized medicine
科学家们希望可以用干细胞来创建一种非常特别的个性化医疗手段，
in which we could replace your own body parts with, well, your own body parts.
用我们自身的一部分，嗯，来代替身体的另一部分，自给自足。
Stem cell researchers are working hard to find ways
干细胞研究人员竭力想要找到一种方法，
in which to use stem cells to create new tissue to replace the parts of organs that are damaged by injury or disease.
可以利用干细胞来培育新的组织，代替器官中由于受伤或者疾病而受损的的部分。
Using stem cells to replace damaged bodily tissue is called regenerative medicine.
利用干细胞取代受损的人体组织的方法叫做再生医学。
For example, scientists currently use stem cells to treat patients with blood diseases such as leukemia.
比方说，现在科学家们正在利用干细胞对患有血液疾病，例如白血病的病人进行治疗。
Leukemia is a form of cancer that affects your bone marrow.
白血病是癌症的一种，可以影响骨髓的正常功能。
Bone marrow is the spongy tissue inside your bones where your blood cells are created.
骨髓是骨头内部制造血细胞的海绵状组织。

In leukemia, some of the cells inside your bone marrow grow uncontrollably,
当患有白血病时，一部分骨髓内的细胞开始不受控地生长，
crowding out the healthy stem cells that form your blood cells.
把生成血细胞的健康干细胞排挤出去。
Some leukemia patients can receive a stem cell transplant.
一些白血病患者可以接受干细胞移植。
These new stem cells will create the blood cells needed by the patient's body.
这些新的干细胞能够制造病人身体所需的血细胞。
There are actually multiple kinds of stem cells that scientists can use for medical treatments and research.
有很多种不同的干细胞都可以被科学家用来进行医疗和研究。
Adult stem cells or tissue-specific stem cells are found in small numbers in most of your body's tissues.
人体大部分的组织中都可以找到少量成体干细胞或者组织特异性干细胞。
Tissue-specific stem cells replace the existing cells in your organs as they wear out and die.
组织特异性干细胞能够取代器官中现有的老化或死亡的细胞。
Embryonic stem cells are created from leftover embryos that are willingly donated by patients from fertility clinics.
胚胎干细胞可以从多余的胚胎细胞中获得，这些胚胎细胞是由生育诊所里一些愿意捐赠的患者那里获得的。
Unlike tissue-specific stem cells, embryonic stem cells are pluripotent.
与组织特异性干细胞不同，胚胎干细胞有很多种功能。
This means that they can be grown into any kind of tissue in the body.
这就是说它们可以生长为身体中任何种类的组织。
A third kind of stem cells is called induced pluripotent stem cells.
第三种干细胞叫做诱导多功能干细胞。
These are regular skin, fat, liver, or other cells that scientists have changed to behave like embryonic stem cells.
这些细胞可以是普通的表皮、脂肪、肝或者其他种类的细胞，而科学家们已经能够将它们转变为具有胚胎干细胞功能的细胞。
Like embryonic stem cells, they, too, can become any kind of cell in the body.
类似于胚胎干细胞，它们也能够成为身体里任何种类的细胞。
While scientists and doctors hope to use all of these kinds of stem cells to create new tissue to heal your body,
科学家和医生们希望能够利用所有这些种类的干细胞来制造新的组织，帮助身体创伤的愈合，
they can also use stem cells to help understand how the body works.
同时他们也可以利用干细胞来了解人体的工作原理。
Scientists can watch stem cells develop into tissue to understand the mechnanisms
科学家们还可以通过观察干细胞生成为组织的过程，从而了解这一机理：
that the body uses to create new tissue in a controlled and regulated way.
即人体用控制和调节的方式来制造新鲜组织。
Scientists hope that with more research, they can not only develop specialized medicine that is specific to your body
科学家们希望通过更多的研究，不但能够研发针对不同个体情况的特异性药物，
but also better understand how your body functions, both when it's healthy and when it's not.
而且能够更好地了解人体在健康和非健康状态下是如何工作的。