Should research on human embryos be permitted beyond 14 days?
The study of embryo formation and development is crucial to understand the processes underlying the early stages of human development and to pinpoint the causes of pregnancy loss.
A recent episode of BBC Inside Science, titled 'Human embryo research and ethics' and hosted by journalist and writer Gaia Vince, discussed the major approaches currently used to study embryo development and their limitations.
In particular, the 14-day rule, promoted by international bodies such as the International Society for Stem Cell Research and enshrined in UK law by the Human Fertilisation and Embryology Act of 1990, has significant implications. It limits research on intact human embryos to up to 14 days after fertilisation.
The rule stood unchallenged for many years, partly because scientists couldn't grow embryos in the lab for more than four or five days anyway. Nonetheless, times have now changed, scientists have made remarkable progress in embryonic research and, as a result, the possibility of extending the rule is now being widely discussed.
The episode featured the bioethicist Professor Insoo Hyun of Case Western University, Ohio, and Harvard Medical School, Massachusetts, and Dr Naomi Moris of the Crick Institute, London, who addressed whether this 14-day limit on human embryo research should be updated.
I really liked how Vince immediately dove into the key theme of the podcast: why were precisely 14 days chosen as a cut-off point for studying intact embryos and was it a reasonable choice? This gave Professor Hyun the opportunity to properly introduce the context of the debate. He explained that 14 consecutive days of development after fertilisation is a pretty significant event in embryo development because that is the first time scientists are able to see embryo formation and elongation under the microscope making it – according to Professor Hyun - a pretty reasonable stopping point for research, from both a legislative and a scientific perspective. This answer, which seems quite supportive of the 14-day rule and of how it was developed, honestly took me a little by surprise, given the nature of the paper he recently published in Science, which dismisses the policy as outdated (see BioNews 1086).
During the discussion, we also learn about the 'black-box' period, which I thought was one of the most intriguing points covered in the episode. This refers to the time period of embryo development between 14 and 28 days that hasn't been thoroughly studied yet. Importantly, many spontaneous miscarriages happen during the black-box period, accounting for 43 percent of all miscarriages. I was really interested to hear about these data, I had never realised how common early pregnancy loss is and how expanding the understanding of human embryo development represents a key stepping-stone to address it.
The conversation then touched on again whether it makes sense to have this 14-day policy today. I felt like at this point Professor Hyun's opinion on the matter here substantially shifted from what he said earlier on and was instead more in line with his latest published article. He suggested that an incremental approach to both research and policies could be the most sensible way to improve embryo growing methods in the dish as well as to implement policies that make sense.
'We need to take small steps and assess each time whether this is useful and valuable information and re-assess every time we need to make a step forward' he concluded.
I thought that in this instance he put forward a balanced and systematic approach to change, which is extremely valuable especially when handling such delicate matters intertwining scientific research and ethics.
Vince then introduced Dr Moris, who studies early embryo development using stem cell structures that resemble embryos but could never survive inside a woman's womb. Importantly, these artificial embryos aren't subject to the 14-day rule and they can therefore be grown to study the black-box period.
I felt Dr Moris' explanations ended up being more convoluted and detailed than necessary, but it was very fascinating to hear about these models, also known as 'stembryos', which provide an interesting alternative to embryo studies.
I thought this was the logical continuation of the earlier discussion with Professor Hyun, providing an exhaustive insight into what the different approaches are and what are their benefits and drawbacks, implying that different experimental systems should be used in parallel to answer all of the questions we are interested in.
This episode gathers excellent discussion points for the ethical debate about embryo development studies. In my opinion, both guests presented a clear picture of the current scenario in the field, however, a less scientifically-minded audience might get lost, as many technical words are used to explain the underlying biology. I would therefore recommend this podcast to those with some background knowledge or genuinely interested individuals prepared to google a few terms!
Vince is clearly an experienced and capable science communicator, she is a breath of fresh air and I thought her questions were very interesting and to-the-point, which made this podcast even more enjoyable. I look forward to finding out more and will be keeping an ear out for any related developments.