45 patients with autosomal dominant polycystic kidney disease (APKD) were interviewed with regard to their knowledge about the familial nature of their disease. 22 patients (mean age up to 57 years) were treated with chronic dialysis, and 23 (mean age up to 49 years) had either normal serum creatinine or chronic renal failure without dialysis (serum creatinine range 1-7 mg/dl). Most of the patients knew the name and prognosis of their disease, but only 9% of them knew that half of their children might be at risk. Only 38% of the patients wanted to know that they had APKD before they had children and only 18% would not have had children if they had known beforehand that they were ill. 45% of the patients on dialysis and 78% of the patients not on dialysis would have had children in spite of their disease. The difference between the two groups is significant (p = 0.006). There was a correlation between the duration of follow-up of the patients and their children's knowledge (r = 0.38; p = 0.017). Genetic counseling in Israel is similar to that in other countries, but there is a large difference between the patients in Israel and others regarding their attitude towards childbearing. The finding of a linkage between a polymorphic region on chromosome 16 (3' HVR) to the locus of APKD makes a prenatal diagnosis of the disease possible. This could be a valuable tool for efficient counseling in the future.