Data were obtained from three samples of women of childbearing age. One sample of women is from prenatal clinics serving Plains Indian women. The second sample is of women from the Plains whose children were referred to special diagnostic developmental clinics, as their children were believed to have developmental issues consistent with prenatal alcohol consumption. The third sample is of women from South Africa, each of whom has given birth to a child diagnosed with full fetal alcohol syndrome (FAS). Data across samples conform to expected trends on many variables. For example, the maternal age at time of pregnancy, a major risk factor for FAS, ranged from a mean of 23.5 years for the prenatal clinic sample, to 23.8 years for the developmental clinic sample, to 27.6 for the sample of women who have delivered children with FAS. Other variables of maternal risk for FAS expected from the extant literature, such as high gravidity and parity, binge drinking, heavy intergenerational drinking in the mother's extended family and immediate social network, and length of drinking career, were compared across the three samples with variable results. However, normative measures of drinking problems are unreliable when reported across cultures. An unexpected finding from this three-sample comparison was the differential risk found when comparing U.S. women to South African women. Women in the U.S. Plains Indian samples report a high consumption of alcohol in a binge pattern of drinking, yet there is less detectable damage to the fetus than among the South African women. Body mass index (BMI) and lifelong and current nutrition may have a substantial impact, along with the above factors, in relative risk for an FAS birth. The level of risk for producing a child with FAS is influenced by environmental and behavioral conditions that vary between populations and among individual women. Also, because many syndromes are genetically based, there is a need for full behavioral and genetic histories of the mother, family, and child being studied. Collecting extensive behavioral information as well as genetic histories will provide the requisite information for making an accurate diagnosis of FAS. © 2004 Wiley-Liss, Inc.