An information leaflet, inviting participation in an antenatal screening trial for cystic fibrosis, was sent to 388 couples together with the pregnant woman's first clinic appointment. The leaflet pointed out that couples would be treated as a unit and that further action would be taken only if both partners were found to carry mutant alleles. Participants and non-participants were also asked to fill in a questionnaire eliciting their views on the leaflet. Three hundred and twelve (80%) questionnaires were returned and 253 (65%) couples elected to be screened. More than 90% of respondents found the leaflet easy to understand, although about 10% wanted more information on cystic fibrosis. The main reason for entering the trial was to avoid the birth of an affected child, and the main reason for non-entry was opposition to termination of pregnancy. There was little anxiety about the prospect of being screened. However, more than a third of couples mis-identified their risk of both carrying a CF gene, despite the figure of 1 in 600 being explicitly stated in the leaflet.