Objectives: This study aimed to assess suicidal ideation based on gender, age, marital status and heritability coefficient estimate in a sample of 11 to 35 years-old monozygotic and dizygot twins. Method: One hundred and sixteen twins (MZ=66, DZ=50 age, 11-35) were invited to complete the Suicide Ideation Scale (SIS) in the anniversary of Laleh and Ladan. Results: Analysis of variance showed th...