Dr Tessa Homfray is an Adviser to the Progress Educational Trust (PET), and a Consultant in Medical Genetics at St George's University of London's Department Of Clinical Developmental Sciences. She runs prenatal clinics at St George's Hospital and at the Harris Birthright Research Centre for Fetal Medicine at King's College Hospital, and she has led working groups on non-invasive prenatal diagnosis for the Joint Committee on Medical Genetics (run by the British Society for Human Genetics, the Royal College of Pathologists and the Royal College of Physicians) and for the Foundation for Genomics and Population Health.