A study of the reproductive outcomes and health of children fathered by Vietnam veterans was conducted. The study was part of a multidimensional assessment of Vietnam veterans' health. The cohort consisted of 7924 veterans entering the United States Army (SIC- 9711) during the period 1965 to 1971 who served in Vietnam and 7364 not serving in Vietnam. Subjects were interviewed by telephone to obtain information on all children they fathered. Incidence rates of adverse reproductive outcomes and birth defects were determined. Hospital birth records were obtained and reviewed. In a substudy, birth records of 294 children with possible cerebrospinal malformations (CSMs) were reviewed to determine their prevalence. Vietnam veterans reported more adverse reproductive and child health outcomes than nonVietnam veterans, prevalence rates being 64.6 and 49.5 cases per 1000 births. Prevalence rates determined from hospital records, however, were similar, 72.6 cases/1000 for Vietnam veterans and 71.1 cases/1000 for nonVietnam veterans. Adjusted odds ratios for major, minor, and suspected birth defects for Vietnam veterans compared with nonVietnam veterans were 1.1, 1.0, and 0.9, respectively. Five cases of CSM were identified in stillbirths in Vietnam veterans versus six in nonVietnam veterans. Twenty one CSM cases were identified in live births of Vietnam veterans and six in live births of nonVietnam veterans. More pregnancies fathered by Vietnam veterans ended in miscarriage than nonVietnam veterans. Vietnam veterans reported more health problems in their children for most disease categories than nonVietnam veterans. No significant differences in infant or child mortality were reported between Vietnam and nonVietnam veterans. The authors conclude that although more Vietnam veterans report more adverse reproductive and child health outcomes than nonVietnam veterans, hospital records show that Vietnam veterans do not have an increased risk of fathering children with birth defects. These findings are consistent with those of three other epidemiological studies.