Why I think PGT-P should be legalised in the UK

This is not a theoretical debate. Patients in the UK are already accessing preimplantation genetic testing for polygenic traits (PGT-P), despite it being illegal here. The only difference is that they are doing so without the protection, guidance, and clinical support that UK regulation is intended to provide.

PGT-P is often portrayed as a radical new technology. In reality, it is an extension of tools that have been used safely and legally in the UK for many years. The embryos involved have already undergone IVF, biopsy, and genetic testing. What changes is not the procedure, but how the data is interpreted and used.

To understand the debate properly, it is important to clarify what PGT-P actually is. PGT for aneuploidy (PGT-A) assesses whether an embryo has the correct number of chromosomes, identifying embryos that are euploid and suitable for transfer, since aneuploidy is the main cause of miscarriage. PGT-M tests for a specific single gene condition such as cystic fibrosis, Huntington's disease, or BRCA-related cancer risk. PGT-P analyses the combined effect of many genes to estimate relative risk for common, complex conditions influenced by multiple genetic variants.

PGT-P does not diagnose disease, and does not predict outcomes. It provides probabilistic information about relative risk for conditions such as type one and type two diabetes, cardiovascular disease, coronary artery disease, hypertension, hypercholesterolaemia, schizophrenia, bipolar disorder, Alzheimer's disease and a range of common cancers.

Importantly, it also offers the potential to better understand genetic contributors to miscarriage and implantation failure, particularly in cases where embryos are already known to be euploid. Euploidy is not the only genetic cause of pregnancy loss, and ignoring available data does not serve patients.

The results of PGT-P are probabilistic, and critics often cite this as a reason to prohibit it. Yet IVF itself is probabilistic. With only around one-third of IVF cycles resulting in a live birth, uncertainty is inherent in reproductive medicine. Across healthcare, clinicians and patients use probabilistic tools every day, from cancer risk models to cardiovascular risk calculators. Reproductive genetics should not be treated differently simply because it challenges existing norms.

Despite this, PGT-P is illegal in the UK. This is not because the science itself is unsafe, but because of how the law is written. The Human Fertilisation and Embryology Act permits embryo testing only for narrowly defined purposes, such as chromosomal abnormalities or serious single-gene conditions. Polygenic conditions do not fit neatly into these categories. As a result, an entire technique has effectively been made illegal due to outdated legislative definitions rather than clinical risk. Making a technique illegal simply because the law has not evolved makes no ethical or medical sense.

The UK has updated fertility laws before when patients' needs, ethics, and social reality demanded it. In 2005, donor anonymity was removed (see BioNews 302), giving donor-conceived adults the legal right to access identifiable information about their donor once they reached adulthood and prioritising long-term welfare over historical convenience. In 2015, mitochondrial donation was legalised after extensive public and parliamentary debate, allowing a powerful genetic technology to be used safely within a tightly regulated framework rather than driven overseas (see BioNews 792, 826 and 1298).

More recently, embryo and gamete cryostorage limits were extended from ten years to up to 55 years (see BioNews 1111), reflecting modern reproductive lives and preventing the unnecessary loss of embryos that remained clinically, emotionally, and ethically important to patients. These changes show that UK fertility law evolves when fixed rules no longer serve patients' best interests. Legalising and regulating PGT-P would follow this same patient-centred, evidence-led approach, rather than pretending the technology does not exist.

The most common objection to PGT-P is fear of eugenics and selection based on non-medical traits such as intelligence or height. These concerns are valid and must be taken seriously (see BioNews 1320). Some of the advertising seen in the USA, particularly in New York, has been deeply unethical, with slogans such as 'Have your best baby' or claims about the genetics of IQ.

I do not support selecting embryos for intelligence or cosmetic traits, and strongly suggest that there should be clear ethical limits on what information can be used. However, banning an entire category of testing because of potential misuse has not prevented misuse. It has simply pushed it outside the UK regulatory framework.

Earlier this year, two patients at my clinic – Avenues – informed us that they had exercised their legal right under the General Data Protection Regulation to obtain their embryos' raw genetic data from the laboratory that performed their PGT-A testing, and had sent the data to a USA-based company for polygenic analysis (see BioNews 1319). This was done entirely legally. In fact, it would have been illegal for the laboratory to refuse the request. The clinic was not involved and could not advise, interpret results or ensure counselling, yet remained responsible for clinical care.

This contradiction is central to the problem. Patients have a legal right to their genetic data. They can legally send this data abroad, and legally receive polygenic risk scores. What is illegal is for UK clinicians to support patients in understanding that information, particularly when deciding which embryo to transfer. From a patient safety perspective, this is illogical.

It is also important to acknowledge how embryo selection already works. Regardless of whether patients have had PGT-P, consent-to-thaw forms in HFEA-licensed clinics across the UK routinely ask patients whether they have a preference for which embryo should be transferred. Patients are not legally required to explain their reasoning. Once embryos have undergone PGT-A, clinics are already selecting among euploid embryos suitable for transfer. Morphology is largely irrelevant at this stage. Selection has already occurred.

By banning PGT-P, the UK has not stopped embryo selection. It has simply prevented clinicians from supporting patients transparently and safely, in decisions that patients are already entitled to make.

The result is a two-tier system. Patients with financial means can access overseas providers, those without cannot. Some patients receive high-quality interpretation, while others are exposed to unregulated commercial services. Clinics are excluded from the process, and are unable to fulfil their duty of care. This is not good regulation.

The legal distinction between single-gene and polygenic conditions is technical, not ethical. What matters to patients is impact. A parent living with type 1 diabetes understands the lifelong consequences of that condition. That parent is trusted to screen embryos for BRCA mutations or Huntington's disease. Denying choice solely because a condition is polygenic, rather than single-gene, is inconsistent and unjustifiable.

This is not about designing perfect children. It is about respecting patient autonomy, and recognising that risk reduction is a legitimate medical goal.

I am proud of the HFEA and the role it has played in building public trust in IVF. The UK is rightly regarded as a global leader in fertility regulation. But leadership requires adaptation. The current position on PGT-P is not enforceable, does not protect patients, and drives care offshore.

Legalising PGT-P does not mean encouraging it or making it routine. It means regulating PGT-P responsibly. It means defining limits, restricting use to health-related information, mandating counselling, ensuring transparency, and holding providers accountable. Most importantly, it means keeping patients within a regulated UK system.

PGT-P is already here. Pandora's box is already open. The choice is not whether it exists, but whether we continue to pretend it does not. Legalising PGT-P would allow the UK to regain control, protect patients, reduce inequality, and lead the world in responsible fertility innovation. If a law no longer serves patients' best interests, then the law needs to change.