Prenatal genetic services are currently available in all but a few states. The Council of Regional Networks for Genetic Services (CORN) has developed and implemented a data collection project to collect a minimum data set (MDS) on genetic services, including prenatal services, throughout the US. More than 400 reporting units were solicited for data in 1989, and approximately 240 (60%) responded. The CORN MDS Report for 1989 shows that more than 124,000 prenatal patients received services in the reporting centers. These individuals received almost 303,000 individual prenatal clinical services and accounted for more than 481,000 laboratory tests. Advanced maternal age was the primary indication for service in the vast majority of patients (62%). Based on data from the two major proficiency testing programs for laboratories performing screening tests for maternal serum alpha-fetoprotein (MSAFP), it is estimated that 50% of the pregnancies in the US are screened for MSAFP. The CORN database provides the only data available for the rapidly expanding area of genetic services. Therefore, it provides a unique resource for evaluating progress toward the Healthy People 2000 objectives regarding genetic services.