Ante-natal screening aims to identify genetic carriers of sickle cell/thalassaemia in order to provide prospective parents with “informed choice”. Since 2008 the NHS in England has used a Family Origins Questionnaire in connection with sickle cell/thalassaemia screening derived from our research programme. The original policy issue concerned whether or not it is possible/desirable to target antenatal screening for sickle cell/thalassaemia by means of an ethnicity question. The policy problem was that socially constructed ethnicity categories correspond imperfectly to an unknown degree with actual prevalence of genetic carriers. The screening question based on our research now guides the offer of initial screening and/or further laboratory tests for all pregnant mothers in England.