This study examined whether psychosocial variables predict pregnant women's attitudes toward maternal serum screening and invasive diagnostic testing, beyond the influence of traditional obstetric risk status (based on advanced maternal age, history of genetic disorders, etc.). In a sample of 612 pregnant women (66.5% high risk, 33.5% low risk) we assessed responses to hypothetical scenarios of invasive testing following normal or abnormal maternal serum screening. We also assessed psychosocial variables stemming from the theory of planned behavior (e.g., knowledge, concern for fetus, attitudes toward termination, health locus of control). Overall, two thirds of the women would want serum screening. Follow-up invasive diagnostic testing would be sought by 37.2% of the women after a negative screening, and by 75.0% after a positive screening. As expected, traditional risk status predicted desire for screening and also invasive testing following either a negative or positive screen. Yet, controlling for risk status, many psychosocial variables predicted a women's interest in screening and in invasive testing: more knowledge about prenatal testing, concern about fetal health, willingness to terminate a pregnancy, and an internal or medical profession health locus of control. We conclude that psychosocial variables influence women's desire for screening or invasive testing beyond traditional risk status.