Medical Genetics On the other hand the inheritance of quantitative traits could not be used to predict outcomes, only average estimates measured in large population studies Mendelians considered the study of quantitative traits to be trivial because they had no predictive valueMedical Genetics On the other hand, the inheritance of quantitative traits could not be used to predict outcomes, only average estimates measured in large population studies. Mendelians considered the study of quantitative traits to be trivial because they had no predictive value