Academics and researchers from The Future of Human Reproduction team have contributed to a Government policy briefing on human stem cell based embryo models (SCBEMs), which has been published by the Parliamentary Office for Science and Technology (POST).

The POSTnote, which incorporates contributions from a wide range of experts, including Dr Laura O’Donovan, Professor Sara Fovargue, Professor Stephen Wilkinson and Dr Nicola Williams from The Future of Human Reproduction team, will inform MPs and parliamentary staff about the scientific development of SCBEMs and the related ethical and regulatory issues raised by this new biotechnology.

SCBEMs are embryo-like structures, created in a laboratory, using human stem cells rather than eggs and sperm. These models mimic the processes that occur in early human embryo development. Scientists hope that research on SCBEMs will lead to valuable insights into why so many pregnancies fail during the first 21 days of embryo development and why congenital birth anomalies, such as spina bifida, occur.

Despite the willingness of many individuals to donate embryos produced during IVF for research, there remains a shortage of high-quality embryos for this purpose. This lack of suitable research materials is one of the drivers for the development of SCBEMs.

“SCBEMs are potentially highly reproducible, making multiple embryo models available for research purposes”, said Professor Wilkinson, Principal Investigator of The Future of Human Reproduction programme.

“They may also provide valuable insights into early human embryo development, which could eventually lead to a reduction in the number of early miscarriages and congenital birth anomalies. However, these models also raise important ethical and regulatory issues, which have been highlighted in the POSTnote.”

“Most fundamentally there is the question of at what point these models become so much like actual embryos that they should be treated as if they were embryos for ethical and regulatory purposes. Currently, while these models can mimic aspects of human embryo development, they cannot develop into the equivalent of postnatal stage humans. However, this may eventually become possible and so we need to consider the implications of that now.”

In November 2023, the Human Fertilisation and Embryology Authority (HFEA), the UK’s fertility regulator, published a series of recommendations on modernising UK fertility law. SCBEMs were identified as being a pressing concern and it was recognised that regulation needs to be ‘future-proofed’ so that it can keep pace with rapidly developing biotechnologies like SCBEMs.

The Human Fertilisation and Embryology Act 1990, as amended, regulates research on human embryos. Human embryos cannot be kept or used after the appearance of the primitive streak, a distinct biological stage which marks the point when an embryo is individuated and can no longer cleave into twins. This is legally taken to occur no later than the end of 14 days, beginning with the day on which the process of creating the embryo began (known as the 14-day rule).

There is a broad consensus within the scientific community that the SCBEMs currently in development are models and not embryos but, as reported in the POSTnote, there is a lack of clarity about whether and how these models fit within the current regulatory framework.

“There is an important question about whether the current provisions in the HFE Act also apply to SCBEMs, and this is creating uncertainty about what is legally permitted in terms of research”, said Professor Fovargue, Co-Investigator on The Future of Human Reproduction programme.

“One of the grey areas is whether the 14-day rule should apply to SCBEMs. This presents a particular challenge because, unlike embryos, there is no ‘day zero’ of conception for SCBEMs as they are not produced via fertilisation. This makes it difficult to apply a biological time-limit to the cultivation of these models. There is also currently no international consensus on how to regulate SCBEMs”.

Uncertainty surrounding the regulation of new biotechnologies, like SCBEMs, can lead to public concern. In response, Cambridge Reproduction has begun to develop a governance framework for SCBEMs, which is expected to be published later this year.

It is also hoped that the POSTnote will put the ethical and regulatory issues raised by SCBEMs on the parliamentary agenda so that some of the uncertainty around the regulation of these models can begin to be addressed.

To find out more, read our blogs about SCBEMs and the 14-day rule.

Published: 29th February 2024