Research over the last 20 years has considerably changed the understanding of the natural history and prognosis for individuals with a diagnosis of sex chromosome aneuploidy (SCA). A cross-sectional retrospective analysis of factors influencing parental decisions following a prenatal diagnosis of SCA during the time period of 1971-97 was performed. The records of 169 fetuses with a prenatal karyotype of 45,X, 47,XXX, 47,XXY, and 47,XYY were reviewed. Mosaic karyotypes for SCA were also included. Information reviewed involved: parental decision, the type of SCA, the presence or absence of mosaicism, the presence or absence of a fetal anomaly diagnosed by ultrasound examination, indication for prenatal diagnosis, prenatal procedure performed, parental age, marital status, previous pregnancy history, family history, ethnicity, religion, education, and profession. A significant correlation was found between the decision to continue a pregnancy and the type of SCA and the presence of fetal abnormalities on ultrasound examination. In addition, this study examined differences in parental decisions over time for the years in question. A statistically significant trend was observed with a higher rate of pregnancy continuation in the more recent years.