Amniocentesis is now commonly used in many countries; it is important to know whether there are any long-term adverse effects on children born after this procedure, in particular disabilities that may emerge during childhood or adolescence. We studied consecutive liveborn offspring of women who had had amniocentesis and compared them with matched controls whose mothers had not had amniocentesis. The controls were matched for age of mother, residence by geographic health unit, sex, and when the birth occurred. 1296 cases and 3704 controls were studied. With the exception of one disorder, the offspring of women who had had amniocentesis were no more likely than controls to have a registrable disability (such as hearing disabilities, learning difficulties, visual problems, and limb anomalies) during childhood and adolescence. The follow-up period was 7-18 years. Children of women who had amniocentesis had a significantly higher rate of haemolytic disease due to ABO isoimmunisation than matched controls. The results of this study should therefore be reassuring to women having amniocentesis, and be useful to women making decisions about having this procedure.