is 14 days. But in light of advancements that may  

是14天。但是，鑑於可能出現的進步

now make it possible to culture embryos beyond  those 14 days, scientists and ethicists are discussing:  

現在，科學家和倫理學家正在討論，使培養超過這14天的胚胎成為可能。

should growing human embryos in a  lab beyond this point be allowed?

是否應該允許在實驗室中培養人類胚胎超過這一點？

Okay, hold up. What do we mean when we  talk about lab-grown embryos? Typically,  

好吧，等一下。當我們談論實驗室培育的胚胎時，我們是什麼意思？通常情況下。

these are fertilized embryos that have been donated to scientific  research by in vitro fertilization clinics because  

這些是由體外受精診所捐獻給科學研究的受精胚胎，因為

the embryo is no longer viable for an IVF treatment.  These embryos are different from embryoids.

胚胎對於試管嬰兒治療來說不再是可行的。 這些胚胎與胚胎不同。

Embryoids are structures that resemble an early  human embryo but they lack some of the cell types and  

胚胎是類似於人類早期胚胎的結構，但它們缺乏一些細胞類型和功能。

structure to develop into something fully viable.  These are often created in a lab from embryonic  

結構，以發展成完全可行的東西。 這些通常是在實驗室裡從胚胎中創造出來的。

stem cells, and they can be a useful tool for  studying lots of aspects of human development.

幹細胞，它們可以成為研究人類發展的許多方面的有用工具。

One recent groundbreaking method uses another kind  of stem cell. Scientists take skin cells and hit  

最近一種突破性的方法使用了另一種幹細胞。科學家們利用皮膚細胞，將其打入

rewind: they reverse them into pluripotent stem  cells, or cells that can essentially develop into  

逆轉：他們將它們逆轉為多能幹細胞，或基本上可以發育為

any tissue type.  

任何組織類型。

And by exposing them to the right environment,   those cells can be coaxed

而通過將它們暴露在正確的環境中，這些細胞可以被哄騙。

into forming a structure that's really similar to

形成一個真正類似於

the earliest stage of a human embryo, called  a blastocyst. But because these didn't develop  

人類胚胎的最早階段，稱為囊胚。但是，由於這些沒有發育

from an actual embryo, they are not quite the same as  a real blastocyst, they are called blastoids instead.

它們來自一個實際的胚胎，與真正的囊胚不完全相同，它們被稱為囊胚。

The existing 14-day limit on lab-mediated human  embryo or embryoid development was suggested after the first  

現有的對實驗室介導的人類胚胎或胚胎體開發的14天限制是在第一次提出後提出的。

IVF babies were born in the 1970s. The media  started to refer to these individuals as 'test  

20世紀70年代，試管嬰兒誕生了。媒體開始將這些人稱為 "試驗品"。

tube babies', and the scientific community wanted  to make it very clear that embryos were not being  

科學界希望非常清楚地表明，胚胎並沒有被用於生產 "試管嬰兒"。

developed into fully viable fetuses in a test  tube. Instead, IVF is when an egg is fertilized  

在試管中發育成完全可行的胎兒。相反，試管嬰兒是在卵子受精後

with sperm in a petri dish, and those fertilized  eggs usually grow for 2 to 5 days in a lab

培養皿中的精子，而這些受精卵通常在實驗室中生長2至5天。

before being transferred to the patient's  uterus—and that's technically a lab-grown embryo.

在被轉移到病人的子宮之前，這在技術上是一個實驗室培育的胚胎。

Now, growing an embryo into a fully fledged baby  in a lab, something called ectogenesis, is still  

現在，在實驗室裡將胚胎培育成一個成熟的嬰兒，即所謂的異體生成，仍然是

totally in the realm of science fiction. But after  the development of IVF, there was growing concern  

完全屬於科幻小說的範疇。但是在試管嬰兒的發展之後，人們越來越擔心

that maybe developing embryos were being experimented on  or thrown away past certain points in development.

也許正在發育的胚胎在發育的某些階段被實驗或被扔掉。

And as the debate rages worldwide  about when life begins, this is and was

當全世界都在爭論生命何時開始的問題時，這就是，也曾經是。

understandably a very thorny issue. So a U.S. regulating body proposed  

可以理解，這是一個非常棘手的問題。是以，美國的一個監管機構提議

the 14-day rule just as a guideline, and that limit  actually became a law in at least a dozen countries.

14天的規則只是作為一個準則，而這個限制實際上在至少十幾個國家成為了法律。

Why 14 days in particular?  

為什麼特別是14天？

That's the point at which an embryo develops  something called the primitive streak, which  

那是一個胚胎髮展出一種叫做原始條紋的東西的點，它

is the beginning of the body differentiating into  its separate building blocks. It's also the point  

是身體開始分化為其獨立的組成部分。這也是

at which becoming a twin is no longer possible,  so that's where 'individuality' is assigned.

在這一點上，成為雙胞胎不再可能，所以這就是 "個體性 "被分配的地方。

And until recently we didn't even know how  to keep human embryos or something similar  

而直到最近，我們甚至不知道如何保存人類胚胎或類似的東西

alive in the lab longer than nine days,  so this wasn't really that pressing of a question.   

在實驗室裡活著的時間超過9天，所以這並不是一個真正緊迫的問題。

But 2016 was the year that a couple  research teams got all the way to 13 days.

但2016年是幾個研究團隊一路走到13天的一年。

And ever since, the scientific community has been  grappling with how to deal with these advances  

此後，科學界一直在努力解決如何處理這些進展的問題

in the face of the limit... or if the  limit should be changed altogether.  

在面對限制時......或如果限制應該完全改變。

Because of the advancements in our ability to  grow these structures in the lab for longer,  

因為我們在實驗室中生長這些結構的能力有了進步，可以更長時間地生長。

and the exciting developments in blastoid and  embryoid research, there's now the possibility  

以及囊胚和胚胎研究方面令人振奮的發展，現在有可能

of investigating parts of human development  we've never had access to before. This could  

調查我們以前從未接觸過的人類發展的部分。這可以

help us understand why some miscarriages  happen, or how some birth defects develop.

幫助我們瞭解為什麼會發生一些流產，或者一些出生缺陷是如何形成的。

We'd be able to see the effects of all kinds of  chemicals and medications on embryonic development  

我們將能夠看到各種化學品和藥物對胚胎髮育的影響

and maybe make IVF safer and more effective. 

並可能使試管嬰兒更安全、更有效。

But would a new time limit only mean good things?

但新的時間限制是否只意味著好事？

What about the possibility of  genetically modifying human embryos in  

對人類胚胎進行基因改造的可能性如何？

new ways—we're gonna need to think about  that one REAL hard. And at what point can  

新的方式--我們需要認真考慮這個問題。而在什麼時候可以

scientists ethically say that a blastocyst  is no longer a clump of cells and is instead,  

科學家們在倫理上說，胚胎不再是一團細胞，而是。

a fetus? And what do we do with  a lab-grown embryo at that point?

一個胎兒？而在這個時候，我們該如何處理實驗室培育的胚胎呢？

We're going to need plans in place for all of this.

我們將需要為這一切制定計劃。

Ever since the 14-day rule was  first proposed in the 1970s,  

自從1970年代首次提出14天規則以來。

experts in this field from scientists to  philosophers have known that we would one day  

這個領域的專家，從科學家到哲學家都知道，我們有一天會

have to revisit this because of scientific  advancements. And that day has arrived.

由於科學的進步，必須重新審視這個問題。而這一天已經到來。

The International Society for  Stem Cell Research, or the ISSCR,  

國際幹細胞研究學會，即ISSCR。

released its updated guidelines for  culturing human embryos and embryoids.  

發佈了其最新的人類胚胎和胚胎培養指南。

They are calling for a public conversation  with ethicists, scientists, and regulators

他們呼籲與倫理學家、科學家和監管機構進行公開對話

about the social and ethical issues associated  with going past 14 days. How this may translate  

關於過去14天的社會和道德問題。這可能如何轉化為

into legal changes in some countries remains to be seen, and lots of questions we talked about before remain unanswered.

到一些國家的法律變化仍有待觀察，我們之前談到的很多問題仍未得到解答。

What do you think about extending the  14 day rule? If you're interested in these public

你對延長14天規則有什麼看法？如果你對這些公共

conversations make sure you check out the link in our description for more details.

對話，確保你查看我們描述中的鏈接，瞭解更多細節。

Make sure to subscribe to Seeker for all of your boundary-pushing biomedical news.

請務必訂閱Seeker，瞭解所有推動生物醫學的新聞。

And if you have another stem cell  development you want us to cover on the channel,  

如果你有其他的幹細胞發展，你希望我們在頻道上報道。

let us know. As always, thanks so much  for watching and I'll see ya next time.

讓我們知道。一如既往，非常感謝您的觀看，我們下次再見。