Embryos developed outside the uterus hardly ever make it past a week without being implanted in the womb, but just recently, scientists from the Rockefeller University and Cambridge University have both successfully grown embryos in a lab for 13 days, only to be cut short in order to comply to the legal limit of 14 days.

The revolutionary breakthrough, which shatters the previous record of 9 days, could shed light on the causes of genetic diseases, disabilities, miscarriages and infertility, but at the same time, it also triggers an ethical debate.

Although scientists have already been extensively studying what happens to embryos at the blastocyst stage (pre-implantation period), they have never successfully looked at it beyond the seventh day development.

As mentioned in the press release, both groups used the technique on mouse embryos used by Dr. Magdalena Zernicka-Goetz, leader of the UK research and University of Cambridge Professor.

Creating a nutrient solution that mimics the conditions in the womb and a structure the embryo can "attach" to, it began to divide into group of cells, Huffington Post noted. The environment in the petri dish, allowed the embryos to develop and reorganize past the one-week mark.

"Using the technique, the researchers have shown that the reorganisation of the embryo that normally takes place during early post-implantation development can be achieved in the lab given the right culture conditions," the press release stated.

Goetz said the technique provides a unique opportunity to get a deeper understanding of human development during a stage deemed relevant and crucial as miscarriage usually happens on this stage. Through the lab experiment, they witnessed the three cells that comprise of blastocyst reorganize themselves into a new configuration, forming the future body that consists of the organs,

"This is about much more than just understanding the biology of implantation embryo development. Knowledge of these processes could help improve the chances of success of IVF, of which only around one in four attempts are successful," Dr. Simon Fishel, founder and President of CARE Fertility Group, co-author of one of the two studies published said in a press release.

The resulting studies were published Wednesday in the journals Nature and Nature Cell Biology.
Aside from leading to better understanding of miscarriages and other pregnancy problems, the breakthrough also implies that scientists could soon culture embryos to an even longer time frame.

However, a major issue is whether government should extend the legal limit of 14 days.

As explained by Independent UK, "About 14 days - the limit is also linked to biological changes -- was chosen in the 1980s because it was deemed to be the point at which "individuality" is assigned as twins do not develop after this point."

The Nuffield Council of Bioethics - an independent body that examines ethical issues in biology and medicine - has released a statement about the issue courtsey of Chair of the Council Jonathan Montgomery:

At our annual ‘Forward Look' planning meeting in February, the Council learned of potentially important scientific research that could be achieved by maintaining embryos in the laboratory for longer than 14 days. As a result of that discussion the Council agreed to explore whether arguments for reviewing the 14-day limit are gaining force, in the expectation that any move to review this limit will be likely to generate significant moral controversy and would require careful analysis.

Later this year, the Council intends to bring together invited participants with a range of perspectives on embryo research in order to evaluate whether, after 25 years, there may be persuasive reasons to review this legal limit, or whether the reasons for its introduction remain sound. It will publish a note of that meeting and then consider whether to undertake further work.