In 1978-79 a single-source outbreak of hepatitis C occurred in 2533 women who had received virus-contaminated anti-D immunoglobulin. Children and husbands of 74 women with self-limited, and of 86 women with chronic, hepatitis C were followed up for over 10-15 years. In 3 of 231 investigated children (1.3%) serological evidence for HCV infection was found. However, none of the children developed an apparent or chronic hepatitis. Serum samples of the 94 husbands investigated showed no HCV antibodies or HCV RNA. We consider the risk of intrauterine or perinatal transmission of HCV, as well as that of transmission through close family contacts, to be low. No evidence was found for sexual transmission for women to men.