Genetic counselling endeavours to be nondirective. However, the availability of prenatal diagnosis may direct clients towards accepting and using these methods. It is time to investigate the attitudes of clients in order to monitor the psychological and social effects of new genetic techniques. As prenatal diagnosis was possible for choroideremia (C), but not for retinitis pigmentosa (RP) in 1988-89, we used a questionnaire to compare the attitudes of C and RP patients, their relatives and C carriers to prenatal diagnosis. The response rate was low (35%) and no significant differences between RP and C groups came to light. However, C carriers accepted prenatal diagnosis and also selective abortion more easily, but, on the other hand, they showed more uncertainty than did the other groups. This indicates that the availability of prenatal diagnosis may confuse those concerned. In general, about 60% of all the respondents had a positive attitude to the prenatal diagnosis of RP or choroideremia, though only about 30% would use if for abortion. Over 80% of all the respondents wanted to know the opinion of the genetic counsellor.