Introduction: Biological characteristics of Parents (height, age, nutrition, history of disease, drugs and substances abuse, blood groups and duration of pregnancy) have a fundamental role in the birth of disabled children. This study aimed to compare the boilogical characteristics between Parents with more than one exceptional child and those Parents with more than one normal child in the urban and rural region of Kermanshah province.Materials & Methods: In this causal- comparative research, 800 Parents (400 Parents with more than one exceptional child and 400 Parents with more than one normal child) were selected by a random and multistage sampling method and completed an appropriate checklist (Afrooz, 2008). After collectingdata, they were analyzed using SPSS software the statistical tests, t-test, chi square.Findings: The finding indicated that there were significant differences in father's age, mother's age, mother's age at marriage, duration of pregnancy, good nutrition, and history of disease, drugs and substances abuse, blood groups between the two groups under study (P<0.01). However, there were no significant differences in mother's age at birth of child and mother's height between the two groups (P<0.01).Discussion & Conclusion: The results showed that there are significant differences between biological characteristics of the Parents with more than one exceptional child and the biological characteristics of Parents with more than one normal child. Therefore, with studying biological variables, researchers would be able to prevent the birth of disabled children and finally improve the physical and psychological health of the society.