The present study is aimed to compare family structure percepted and ideal between parents and their young adult children. 367 families (n =U28) including father, mother, and a young adult child (l5-29) were selected .randomly through cluster sampling among families inhabited in Tehran, Isfahan, Tabriz, Sanandaj, and Khonlmabad. All three members completed Family Adaptability and 'Cohesion Evaluation Scale (third version, FACES-III, Olson et at, 1985) separately. Before carrying out the questionnaires, demographic information of family members was adopted by an interview.The results of the present study indicate that there is no significant generation gap in the field of family structure and function (at perceived and ideal levels) and most of the families are placed in a balanced family system. Although, from the perceived family structure point of view, both fathers and mothers have perceived their family structure as "flexible-cohesive", their young children have perceived their real family structure as "disorganizedcohesive".Also, a general addup of the five cities being studied revealed that all three members, including father, mother, and child, described their ideal family structure as "disorganizedcohesive". In other words, they wish more cohesion and flexibility. Moreover, comparing the results is indicative of significant differences between perceived and ideal conditions of youth as well as perceived and ideal conditions of parents. In order to explain the placement of family in a balanced condition and the absence of generation gap, we relied on the balanced family system with a more positive condition in comparison to other family systems and leads to balance and healthy family function. Appropriate adaptability and cohesion in these systems are among the healthy functioning and family structure criteria in circumplex theory of Olson and many other structural theories of family. They might be of the important factors of intergenerational solidarity and agreement. Yet, while explaining parents' and children's differences in cohesion and adaptability conditions, investigators believe that several factors result in different or contrast parent-child views regarding communication (real or hypothetical):different experience of stressors, social environment, different expectations.