An evaluation was carried out into whether neonatal screening for Cystic Fibrosis could potentially prevent the birth of more affected children in the same family. Although CF was detected in more than 50% within the first year of life in those cases where a diagnosis was made on clinical symptoms, in these families 10 children -- among whom two with CF -- were born prior to the CF diagnosis. With neonatal screening, no pregnancies were started before the CF-diagnosis. No differences were found in attitudes toward further reproduction and understanding of important genetic facts. Although prenatal diagnosis was not yet possible at the time of the study, approximately 50% of the parents showed a positive attitude toward this option. Minimizing the delay in diagnosis by neonatal screening, together with the availability of prenatal diagnosis may lead to a significant reduction in subsequent births of CF cases.