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  • The internationally recognized limit for how  long a human embryo can be grown in a lab  

  • is 14 days. But in light of advancements that may  

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

  • should growing human embryos inlab beyond this point be allowed?

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

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

  • the embryo is no longer viable for an IVF treatmentThese embryos are different from embryoids.

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

  • structure to develop into something fully viableThese are often created in a lab from embryonic  

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

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

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

  • any tissue type.  

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

  • into forming a structure that's really similar to

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

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

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

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

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

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

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

  • before being transferred to the patient's  uterusand that's technically a lab-grown embryo.

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

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

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

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

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

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

  • Why 14 days in particular?  

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

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

  • at which becoming a twin is no longer possibleso that's where 'individuality' is assigned.

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

  • alive in the lab longer than nine daysso this wasn't really that pressing of a question.   

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

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

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

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

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

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

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

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

  • and maybe make IVF safer and more effective

  • But would a new time limit only mean good things?

  • What about the possibility of  genetically modifying human embryos in  

  • new wayswe're gonna need to think about  that one REAL hard. And at what point can  

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

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

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

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

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

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

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

  • released its updated guidelines for  culturing human embryos and embryoids.  

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

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

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

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

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

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

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

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

The internationally recognized limit for how  long a human embryo can be grown in a lab  

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B1 embryo lab ivf limit human development

Why Scientists Might Drop the 14-Day Limit on Human Embryo Research

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    Summer posted on 2021/06/04
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