Making decisions to undergo Autism Spectrum Disorders (ASD) genetic testing can be challenging. It is important to understand how the perceptions of affected individuals might influence testing decision-making. Although evidence has shown that psychological factors are important in predicting testing decisions, affect-type variables have been largely ignored among well-established health theories. Using questionnaires, we examined genetic testing decision-making among 444 parents of children with ASD in Taiwan. The largest predictor of intention was anxiety (ß = 0.46, p<0.0001) followed by fear/guilt (ß = -0.041, p<0.000). Attitudes did not predict intention. Affect-type variables should be considered in genetic testing decision making theory, research, and practice.