A significant and ethically charged development is unfolding within UK fertility clinics, where a growing number of couples are reportedly using a legal ambiguity to screen and rank embryos created through IVF based on non-medical traits such as intelligence, height, and future health.
The Legal Grey Area Enabling Embryo Selection
At the heart of this practice lies a specific provision in the UK's fertility laws. The Human Fertilisation and Embryology Act (1990) permits the use of preimplantation genetic testing for monogenic disorders (PGT-M). This is intended to screen out embryos carrying genes for serious, heritable conditions like cystic fibrosis or Huntington's disease.
However, the legislation does not explicitly restrict which genes can be examined. This has created a loophole. Fertility clinics are now offering expanded genetic profiling that analyses polygenic risk scores. These scores estimate an embryo's statistical predisposition to a wide range of characteristics, from educational attainment and IQ to adult height and susceptibility to common diseases like heart disease or type 2 diabetes.
Professor Frances Flinter, a clinical geneticist at Guy's and St Thomas' NHS Foundation Trust and former chair of the Nuffield Council on Bioethics, confirmed the trend. She stated that private clinics are actively marketing this service, allowing prospective parents to choose which embryo to implant based on these complex, probabilistic scores.
How the Embryo Ranking Process Works
The process begins with a standard IVF cycle, where multiple embryos are created. A few cells are then biopsied from each embryo for comprehensive genetic analysis. The resulting data is run through algorithms to generate polygenic risk scores for each embryo.
Clinics then present this information to the prospective parents, often in the form of a ranked list. One couple, who spoke to The Guardian anonymously, admitted they selected an embryo with a lower risk of heart disease and a higher predicted educational attainment score over a sibling embryo. They justified their decision by stating they wanted to give their child "the best start in life."
This practice is currently confined to the private sector, with treatments costing tens of thousands of pounds. It raises profound questions about the commodification of life, the reinforcement of social inequalities, and the move towards a form of commercial eugenics.
Ethical Concerns and Calls for Regulatory Action
The emergence of this practice has sparked intense debate among ethicists, scientists, and regulators. Critics argue it represents a dangerous step towards "designer babies," where children are selected for perceived advantageous traits rather than being valued unconditionally.
There are significant scientific concerns too. Polygenic risk scores are probabilistic and based on population-level data; they are far from deterministic predictors for an individual's future. Selecting an embryo with a supposedly higher IQ score does not guarantee a more intelligent child, as environmental factors play a colossal role.
The Human Fertilisation and Embryology Authority (HFEA), the UK's fertility regulator, has stated it is "closely monitoring" the science. However, it currently lacks clear powers to ban the practice because the law does not specify which genetic conditions are serious enough to warrant screening. This regulatory gap is what clinics are exploiting.
Experts like Professor Flinter are now urging the government and Parliament to intervene. They are calling for an urgent review of the 1990 Act to explicitly prohibit the use of polygenic risk scores for non-medical trait selection, closing a loophole that many believe was never intended to exist.
The debate forces society to confront fundamental questions about the limits of reproductive technology, the definition of a medical condition, and what it means to pursue a "better" child in an increasingly unequal world.
