Parliamentary briefing1st June 2026
Key Messages
- The Human Fertilisation and Embryology Act (HFE Act) 1990 has provided the framework for the UK’s world-leading regulation of fertility treatment and embryo research for more than 35 years.
- Built on the landmark 1984 Warnock report, the Act established a specialist regulator – the Human Fertilisation and Embryology Authority – to support scientific progress while upholding strong ethical standards. The Act’s success and longevity is underpinned by the ethical foundations provided by the Warnock report, however rapid scientific advances are increasingly testing the boundaries of the Act.
- To maintain public trust and support responsible innovation, we believe the Government should act now to future-proof the HFE Act. This is essential to ensure the regulatory framework remains fit for purpose and has the flexibility to respond to the rapid pace of scientific development.
- Our research has highlighted several areas where scientific developments already are outpacing, or may be about to outpace, the current legislative framework. These include stem cell-based embryo models and in vitro-derived gametes.
- In our 2024 report on stem cell-based embryo models (SCBEMs), we concluded that targeted amendments to the HFE Act are now needed to support scientists with regulatory certainty and give the public confidence that appropriate ethical safeguards are in place. Without these reforms, there is a risk of disproportionate legal action, which would effectively halt this promising field of research.
- There are also growing calls for the 14-day rule for embryo research to be extended, which has prompted the NCOB’s current review on embryo research. To be published in Autumn, our research will provide Government with robust, independent evidence on the ethical, scientific and societal implications of possible changes to how embryo research is governed. This includes extensive deliberative public engagement, to ensure that any future reforms are truly reflective of diverse societal views and interests.
- The challenge of innovation outpacing regulation is not unique to embryo research and assisted reproduction. Reform of the HFE Act presents an opportunity to develop ethically informed and adaptive approaches to regulation that support scientific progress in a way that is aligned with societal values. Such approaches should inform innovative governance across the biotechnology landscape.
Background
In 2023, the Human Embryology and Fertilisation Authority (HFEA) – the regulator for fertility clinics and human embryo research – called on the Government to update the Human Fertilisation and Embryology Act 1990.
The HFEA argued that modernisation is needed to reflect changes in the fertility sector, as well as significant scientific advances in embryo and fertility research. The NCOB has similarly highlighted the need to ensure that the regulatory framework remains fit for purpose as science and technology continue to evolve, including through targeted amendments to address emerging technologies.
We have identified two key areas where scientific advances may be outpacing the current legislative framework:
- Stem-cell based embryo models
- In vitro-derived gametes
Given the rapid pace of technological development, there is a strong case for Government to review the Act now, while technologies like SCBEMs and IVG remain in their infancy. This would create an opportunity to develop a more agile and anticipatory regulatory framework, informed by robust ethical analysis and public engagement, that can support beneficial innovation while maintaining public trust and patient safety.
Conversely, failing to act risks missed opportunities for beneficial innovation, reactive regulatory decisions, a loss of public trust in science, and an erosion of the UK’s competitive edge as a global leader in fertility treatment, embryo research and the life sciences.
The 14-day rule for embryo research: calls for reform
The HFE Act limits research on human embryos to a maximum period of 14 days from fertilisation or until the appearance of the ‘primitive streak,’ whichever occurs first. The rule has largely been adopted internationally in jurisdictions that permit embryo research.
Until recently, it was not scientifically possible to sustain human embryos in culture up to 14 days. Advances in embryo culture techniques, however, now mean that embryos are being destroyed at the 14-day limit because of the legal requirement rather than technological constraints.
Many scientists suggest that by extending the limit, we could gain a better understanding of early human development, pregnancy loss and congenital disorders. At present, relatively little is known about human development beyond the 14-day stage.
The prospect of these scientific and medical benefits, together with evidence that there is some public support for an extension to the rule in the UK, has prompted increasing calls to review the rule. The HFEA has also recommended that the limit is extended.
Informing the future of the 14-day rule
As calls for review grow, Government will need access to robust, independent ethical analysis to inform decisions about the future of embryo research regulation.
To provide this, the Nuffield Council on Bioethics (NCOB) is undertaking a major review of the 14-day rule. The project is examining the ethical considerations, emerging scientific capabilities, and public attitudes surrounding embryo research, under the guidance of a multidisciplinary Working Group. Our aim is not to advocate for a particular outcome, but to provide Government with robust evidence on possible future options for embryo research regulation and map their implications.
As part of this review, we have partnered with UKRI Sciencewise to deliver a large-scale public dialogue exploring public views and values on embryo research. This included a Citizens’ Summit involving more than 100 participants broadly representative of the UK population, alongside an extensive series of community conversations with diverse groups that are often underrepresented in medical research.
In November 2025, we published two interim outputs outlining the use of embryos in research and the related ethical debates.
We are due to publish our final report, along with the findings from the public dialogue, in Autumn 2026.
Stem cell-based embryo models
In our 2024 report, we examined the ethical and governance challenges posed by stem cell-based embryo models (SCBEMs) and set out a roadmap for their future regulation. Delivering that roadmap will ultimately require targeted amendments to the HFE Act.
SCBEMs are laboratory-grown models, made from human stem cells, that mimic early stages of human embryonic development. They could improve our understanding of miscarriage, infertility, developmental disorders, and the safety of medicines during pregnancy. However, SCBEM research currently falls outside existing governance and regulatory frameworks in the UK.
As the technology progresses, SCBEMs may raise complex ethical questions, given that they may increasingly resemble and replicate real human embryos or develop features such as the capacity to feel pain.
Future-proofing SCBEM regulation
In 2024 Cambridge Reproduction and the Progress Educational Trust (PET) published a voluntary Code of Practice for SCBEM research. As a first step, we support embedding this system of voluntary governance.
However, in the longer term, voluntary governance alone may not be sufficient to prevent public backlash, erosion of trust, and reactive regulatory intervention by governments or the courts. If research were to outpace public acceptance— for example, the development of SCBEMs with features such as the capacity to feel pain—public outcry could prompt calls for stronger oversight.
One possible response would be to bring SCBEMs within the existing regulatory framework governing embryos. We concluded that regulating SCBEMs as embryos would be inappropriate, disproportionate and unlikely address the distinct ethical considerations they raise. This could also have a have a chilling effect on research in the UK. This risk is not theoretical: a similar legal interpretation has effectively halted SCBEM research in Australia.
To avoid these risks, we recommend three targeted updates to the HFE Act:
- First, clarify that SCBEMs and embryos are distinct for regulatory purposes.
- Second, to legally uphold ethical ‘red lines’ – such as prohibiting the implantation SCBEMs into humans or non-human animals for reproductive purposes – to give the public confidence that ethical guardrails are in place.
- Third, create a regulatory sandbox to support flexible oversight and test approaches to proportionate regulation of SCBEMs.
In vitro-derived gametes
In vitro-derived gametes (IVGs) are sperm and eggs created from stem cells. IVG technology is still at an early stage of development. However, notable progress has been made in animal studies, such as the birth of mice with two biological fathers in 2023. Some scientists predicted that the creation of viable human sex cells may be ‘about seven years away’.
IVGs could create new treatment options for infertility. For example, they could enable people who do not produce viable gametes to have genetically related children. IVGs could also enable same-sex couples to have offspring biologically related to both parents.
However, the technology raises significant ethical questions, as outlined in our report on the Future of Human Reproduction. Before IVG use in human reproduction can be considered, there is a need for public engagement and a thorough consideration of the ethical and legal issues raised by this biotechnology, alongside further research and testing to ensure safety and efficacy.
It is too soon to know whether IVGs will, or should, become part of assisted reproduction. Nevertheless, given predictions that human IVGs could become feasible within the next decade, Government should begin considering the questions they raise now. This includes the conditions under which IVGs might be permitted and how to ensure the regulatory framework remains flexible enough to respond to scientific advances and evolving societal views.